‘You don’t know what you’ve got ‘til it's gone’: Police retention of investigative materials

The seizure, safe handling and secure storage of evidence during criminal investigations is pivotal to the successful detection and prosecution of offences. The safe retention of materials after an investigation closes, even post-conviction, is also critical both to the ability of the appellate system to function and for ‘cold cases’ to be reviewed. Yet despite periodic high-profile instances in which failures to ensure the integrity and retention of evidence have occurred, there is a reticence to admit to evidence being lost; in particular, to consider the issue on an aggregate rather than a case-by-case basis. This lack of transparency is compounded by an accountability deficit, in which the issue falls through regulatory gaps. Provoked to locate proof of lost evidence, this article examines police retention of investigative materials, and details the results of surveys undertaken with lawyers and miscarriage of justice campaigners (n = 65) and police (n = 87), and 21 interviews with serving and retired police officers. We identify ‘weak links’ in the evidence chain that need strengthening, including the enhancement of training, improved physical packaging and storage facilities, sufficient training of police staff and the creation of specialised ‘exhibits’ roles. Further to practical resource demands, the issue requires accessible data so that the problem can be acknowledged, and accountability and oversight mechanisms created to assure processes.


Introduction
It is axiomatic that the police, in their crime investigation role, gather 'evidence'.This can vary wildly in respect of its origins, form and significance, with some generated during an investigation (interview recordings, witness statements, etc.) but a great deal collated/assembled by police for interrogation. 1 It is also self-evident that the assiduous collection, recording and storage/retention 2 of material is key to crime detection and prosecution, but further that the retention of materials is critical to future appeals and for resolving undetected cases when conducting 'cold case' reviews.Examples of 'losses', 3 as well as confusion surrounding the rules and governance of retention of investigative materials and their disclosure, were presented in 2019 by the authors to the Criminal Cases Review Commission (CCRC), who, in essence, responded 'prove there is a problem ', 4 provoking research to determine the scale of the problem, its impact and what measures may mitigate the risks of lost evidence.

The legal and policy framework for evidence retention
The Authorised Professional Practice (APP) guidelines (College of Policing, 2022) state that: 'the investigator must keep accurate and comprehensive records of all exhibits throughout an investigation.As each exhibit is recovered, a record should be compiled detailing the: • precise description of the material recovered • precise location of recovery • time, day and date of recovery • individual who recovered it • location and method of storage'.
As well as detailed record-making, the continuity of exhibits must be maintained with all movement of exhibits recorded and any removal of material from storage (e.g. for forensic examination) recorded, detailing: 'the reasons for the movement, the name of the person who removed it, when it was removed and to whom it has been transferred'.(College of Policing, 2022).In large-scale enquiries it is stated that an exhibits officer be appointed and this officer will ensure that the recovery, handling, storage and submission of all relevant exhibits is undertaken, and that the integrity of exhibits is preserved to avoid contamination, and that all records are maintained on indexes (Association of Chief Police Officers, 2005: para 5.7).
There have been recent changes to both the legal framework for retention and national policy.Assuming that all materials have been collected with integrity and detailed records have been created, there is a statutory framework for the retention of this material by the investigating police force set out in the Criminal Procedure Investigations Act 1996 (CPIA) via a code of practice.The CPIA states that where a conviction has been obtained, physical material must be retained until release from custody. 5 In 2017, the National Police Chiefs' Council (NPCC) published 'Guidance regarding the storage, retention and destruction of records and materials that have been seized for forensic examination (v2.1)', with the Forensic Capability Network reproducing this with further detail in 2021 (Forensic Capability Network, 2021).This 29-page document reiterates that consideration must be given to the CPIA: 'to ensure that materials are held for at least the life of any sentence and the requirements of the Data Protection Act (part 3) to ensure that personal data is not kept for any longer than is necessary' (Forensic Capability Network, 2021: para 11.1.1).
The minimum retention periods as currently set out are: major and serious crime, 30 years; volume crime, 6 years; and less serious crimes, 3 years.There is an argument that these retention periods may be too short and should be lengthened.With sentences on average increasing in length for serious offences, the NPCC retention period of 30 years may often fall short of the requirement in the CPIA 1996 so there is potential for confusion between the CPIA and NPCC.Furthermore, it is near impossible for prisoners who have been wrongly convicted to appeal quickly and it can take decades to re-investigate a case, particularly if the CCRC are involved, and this may take place after release.Now more than ever the police are re-investigating (c)old cases.The Crown Prosecution Service (CPS) cannot prosecute historical cases if there is not sufficient evidence for there to be a realistic prospect of conviction.
Regardless of current retention lengths and their appropriateness, research has revealed confusion among police forces, with the majority citing inappropriate guidance or statute, with worrying inconsistency between forces and confusion over both what material should be retained and for how long (Madland and Shorter, 2019).This confusion is compounded by complications over the post-conviction disclosure of material, supposedly dealt with by the Supreme Court in R (Nunn) v. Chief Constable of Suffolk Constabulary & Anor.
[2014] UKSC 37, when ruling that the police should exercise discretion over whether to disclose materials post-conviction, finding that 'the State only need consider requests to access exhibits, using "sensible judgement", if there is a "real prospect" that it will cast doubt on the safety of the conviction' (McCartney and Shorter, 2019b: 7).
As well as legal and policy changes to retention, there have been seismic changes in the way that forensic investigations are undertaken in England and Wales.Following creation of a national Forensic Science Service (FSS) in 1991, all materials undergoing forensic testing were sent by individual police forces to national facilities, where they were then kept.Since closure of the FSS and the privatisation of forensic testing in 2012 all material is now returned to police forces for storage, including swabs and frozen samples.The necessary investment to replace resources lost with the FSS closure, in terms of both expertise and facilities, has evidently not been provided to police forces (McCartney and Shorter, 2019a).

Locating evidence of lost evidence
With a lack of easily accessible data on lost evidence, and little publicity, it is perhaps understandable that there may be scepticism that this is an issue meriting attention.Hence we undertook to determine the scale of evidence loss and its consequences, including Freedom of Information (FOI) requests to police forces, the CPS and various agencies to seek data on evidence loss.The CPS data give an indication of the potential impact of lost materials on prosecutions, reporting that between October 2018 and August 2021, some 20,838 cases collapsed pre-trial due to missing and lost evidence, including 42 homicides (1.12% of the total homicides prosecuted in that period) and 364 sex offences (1.18% of the sex offences prosecuted).Despite some forces attempting to address issues with the introduction of new software and other practical steps, the problem does not appear to be diminishing nationally, with the data from the last year that have been collated -September 2021 to September 2022showing that 7316 cases were dropped, including 16 homicides (1.27% of the total homicide prosecuted) and 123 sex offences (1%).
Losing investigative material can also mean missed opportunities to detect repeat offenders.In the case of an unsolved 1989 rape of a 16-year-old girl, the loss of case files meant that the police did not upload an offender DNA profile to the newly created National DNA Database (NDNAD) in 1995.In 2000, the perpetrators' DNA was uploaded to the NDNAD in connection with a drink driving offence, but did not 'match' with the rape until 2010, after a trawl of the FSS archives uncovered the 'orphan' profile.A year later a man was finally convicted of the 1989 rape along with a series of other serious sexual offences committed between 1998 and 2010, the period in which the DNA sample was 'missing'.The case gave rise to the Independent Police Complaints Commission (IPCC) 'Operation Kendall' finding that: 'serious shortcomings in the way police forces store and maintain original case papers and exhibits.Widespread destruction and loss of these items has had a serious effect on progressing potentially solvable cases'.(Independent Police Complaints Commission, 2013: 3).The IPCC made a series of national recommendations including: 'Police forces should review their policies on the retention and storage of case files and exhibits in relation to serious crime, including rape and serious sexual assault' and 'Police forces should ensure that they are not destroying information that could be useful in the future, either to take advantage of current forensic technology or any future advances' (Independent Police Complaints Commission, 2013: 2).
Loss of police materials has been implicated in wrongful convictions and evidence retention is crucial for re-examining questioned convictions.Often the revelation of material long believed lost permits a final appeal, satisfying the 'fresh evidence' requirement so that appellate courts can overturn a wrongful conviction.When there is a failure to retain evidence, this vital part of the criminal justice system is hamstrung.In just one example, in the murder of Paula Poolton the investigating force destroyed, contaminated (by inappropriate storage) and lost investigative materials after the conviction of Roger Kearney.Yet Kearney still maintains his innocence and fresh forensic testing could objectively test these claims of innocence, potentially identifying a wrongful conviction and revealing the real killer.
Of course, even with computerised log books and digital record-keeping, it is a significant undertaking to store both the physical items and records of materials, and in particular, their movement during an investigation and possible trial.In an average year, the Metropolitan Police Service (MPS) 6 seizes ∼600,000 pieces of 'property'.Between 2017 and 2021, the MPS recorded 3428 itemsor 0.05%as 'missing' (Metropolitan Police Service, 2021). 7Despite the centrality of evidence and the unexceptional requirement that materials move between the police, forensic service providers (FSPs), the CPS and Courts, links in this chain have proven weak.The CPS have been investigated by the Information Commissioners Office (ICO) for breaches of the Data Protection Act, most recently in 2022, when the CPS were reprimanded after losing case files and unencrypted CDs with recordings of interviews with assault victims (Information Commissioners Office, 2022). 8In 2015, the ICO fined the CPS £200,000 after laptops containing video interviews with victims and witnesses in more than 30 investigations were stolen and again just a year later, the CPS lost unencrypted DVDs containing interviews with 15 victims of child sexual abuse, and were fined £325,000 (Trendall, 2018).
Each police force has standard procedures for the collection and management of materials, in recognition of the centrality of physical evidence in investigations and the critical requirement for exhibits to have integrity.The Metropolitan Police General Orders 1982, 9 instructed that: [E]xhibits were required to be collected and managed to protect against contamination, or any break in the evidence of the continuity of the handling of each exhibit.Exhibits which might need to be forensically examined had to be handled promptly, and in accordance with the standard procedures.Those procedures dictated that gloves should be worn to handle exhibits, which should then be placed into bags, which should be sealed, numbered and labelled, and placed in a secure identifiable place (Daniel Morgan Independent Panel, 2021: para. 966) Yet extensive failures to follow such procedures during the MPS investigation of the murder of Daniel Morgan in 1987 has meant that no one can be sure what evidence was collected or retained: '… since not all exhibits were individually identified, and exhibits were not correctly managed …', the panel concluding that the loss of accountability for exhibits was 'inexcusable' (Daniel Morgan Independent Panel, 2021: para. 973).The MPS were further criticised by Her Majesty's Inspectorate of Constabulary, Fire and Rescue Services (HMICFRS) in 2022, concluding that the situation with exhibit handling and management was 'wholly unsatisfactory' and 'impossible to defend' (Her Majesty's Inspectorate of Constabulary, Fire and Rescue Services, 2022: 7) when such failures persisted: Inexcusably, 35 years after Daniel Morgan's murder, the force had not taken adequate steps to correct all that went wrong during its investigations.Arrangements for the storage of property and exhibits were especially dire: hundreds of items (including cash, jewellery and drugs) could not be accounted for; firearms had not been correctly stored; and some property stores were overflowing and lacked adequate security….'(Her Majesty's Inspectorate of Constabulary, Fire and Rescue Services, 2022: 2) In 2023, the Baroness Casey Review detailed the 'dire state' of police property storage, which has been: 'known about, reported on and investigated before' (Baroness Casey, 2023: 13).Baroness Casey detailed discussions with officers who referred to 'over-stuffed, dilapidated or broken fridges and freezers' (p.15) with freezers containing rape forensic samples 'iced up and taped shut' (p.112) and 'freezers crammed full of evidence samples, which were overflowing, frosted over and taped shut'.(p.147).The report details resourcing issues on a team investigating sexual offences …the unit's freezers, which held and preserved evidence obtained from victims and survivors of sexual violence including swabs, blood, urine and underwear, would be so full it would take three officers to close them: one person to push the door closed, one person to hold it shut, and one to secure the lock.All the fridges used for rape kits were in bad shape, packed and ruining evidence.In the heatwave in 2022, G said that one freezer broke down and all of the evidence had to be destroyed because it could no longer be used.G said a general email had been sent round to this effect and that it meant that all those cases of alleged rape would be dropped.G also said she had 'lost count' of the number of times she had asked a colleague where the necessary evidence was before being told that it had been lost.( Baroness Casey, 2023: 179) Problems with evidence retention can also be witnessed in at least the United States and Canada, where multiple reports into specific criminal cases have featured lost evidence, resulting in either a wrongful conviction or an inability to re-consider a questioned conviction.Data from the Innocence Project found that of the cases closed between 2004 and 2010, a quarter were closed because evidence could not be found or was confirmed destroyed, albeit they recorded: 'at least twenty-eight DNA exonerations which were nearly closed for this reason, but persistence and luck eventually uncovered the evidence in the cases' (West and Meterko, 2016: 723).Again, there is limited (academic) research on the issues surrounding evidence retention, 10 and apparently little concern shown by authorities. 11Indeed, the prevailing anxiety is the retention of evidence (particularly sexual assault examination kits) that go un-tested and create 'backlogs', which the United States have been attempting to address for many years.In both the United States and Canada, there are huge variations in the existence of, and content of retention policies (Campbell, 2018;Roach, 2023).A 2021 document collating US state biological and evidence laws focuses upon DNA samples and sexual assault examination kits, and occasionally property seized or abandoned that the police acquire.There are no legal provisions detailed that govern what we would consider 'investigative materials'. 12

Evidence loss: Survey and interview data
The CCRC scepticism that loss of evidence or perplexity over retention and disclosure requirements were featuring (sufficient to notice) in their investigations also prompted the authors to undertake a series of surveys and interviews to gauge the experience of legal practitioners and police officers.This qualitative data would also provide insight into the practical issues faced by those charged with retaining evidence, and the experience of criminal case workers trying to obtain investigative materials.After obtaining ethical approval from Northumbria University, in collaboration with Northumbria University law students and the charity Inside Justice, a survey of legal professionals and miscarriage of justice campaigners was distributed online to determine the extent to which the retention of materials was impacting upon prisoners' attempts to appeal.Sixty-five respondents completed the survey in December 2019.A second survey was distributed online to police in June 2020.Eighty-seven serving and retired police officers completed the second survey.Both surveys permitted a mixture of quantitative and qualitative data, allowing for detailed written responses as well as responses to closed questions.The second survey was supplemented in July 2020 by 21 follow-up in-person interviews of serving and retired police officers.The survey and interview data were transcribed and underwent thematic analysis to surface the problems of evidence retention and suggestions for potential solutions to evidence loss.

Attitudes towards evidence loss
From the lawyer/campaigner surveys, 73% of respondents (47) had worked on a criminal conviction where evidence has been lost, destroyed or contaminated, with almost half (32) claiming this had happened on multiple occasions; more than one-third (24) stated they had cases where the loss of evidence meant they could not appeal.Among the few legal professionals who gave more details, comments reinforced this sense of the banality of lost material, one respondent simply listing examples of lost items in different offences: 'Robberyweapons, balaclavas, gloves.Rapedefendant's mobile telephone.Murderpolicy file, original records of alternative suspect enquiries.Many casespolice pocket notebooks'.Whether attributable to a terse writing, or simply the speed with which they completed the survey, the overriding impression from the comments of lawyers was that there was almost an inevitability to lost materials: 'I have been in multiple cases where CCTV has been destroyed that the defendant had said, in interview, would exonerate him or her'.Another explained succinctly: 'A rape allegation we were asked to take over.It was not possible to get the material from ** Police in connection with the case.Eventually told it had been destroyed accidentally'.
Police responses and interviews, by contrast, were less stoical, with many voicing serious concerns while relating instances that gave rise to apparent frustrations.Given that there would have been a strong self-selecting bias which meant only those officers who believed retention of materials was worth discussing responded, who were both alert to the issues and keen enough to respondeven more so to undertake an interviewit was not surprising that the majority were critical.Often, however, a censorious tone was tempered with caveats that 'normally' things worked well and examples of bad practice were interspersed with explanations and justifications that removed blame as far as possible from individual officers.Many officers also portrayed the problem of lost materials as an historical issue, being more prevalent in the pre-digital age: 'every case since the 80s has been stored properly'.Problems were placed firmly in the past: IT systems have changed and the information like DNA extracts, have been lost … especially in cold cases.One which springs to mind is 40 years old, which we opened up a couple of years ago, which was a murder investigation and there were just bits of evidence not even in evidence bags, no paperwork whatsoever to go with stuff … it was a different world….
More than three-quarters (67) of police respondents claimed to have experience of an investigation in which they had been unable to locate seized evidence.Further, 65% (57) had experience of a case in which evidence had not been secured, and stored, with the required integrity, security and continuity.However, just 33% (28) claimed that this had impacted the case.Further comments and interviews made clear that this was not an indicator of complacency, but it was clarified that most often, cases were already completed before items were lost/contaminated, or that prosecutions were able to proceed regardless, albeit there were many variations of: 'I've never had a case lost on that basis but I am aware of cases that have folded'.There was acknowledgement of the potentially serious consequences: 'The unfortunate thing is the 2% where people can get off with serious crimes'.Although again recognising the biased sample of people who already viewed this issue seriously enough to take time to complete the survey/be interviewed, most were unsurprisingly eager to see the situation improve and many had suggestions as to how this could be achieved.
Only one officer hinted that bad motives could perhaps be ascribed to officers when claiming that 'surveillance logs are deliberately damaged or lost', another simply alluding to the fact that poor retention practice meant: 'If something is discovered at a later date, that's the worst thing that can happenit looks like it's been hidden'.Instead, the emphasis was on occasions when individuals had apparently buckled under pressure: 'over worked officers storing exhibits in their desk drawers so they can deal with them the following day', and officers might be in difficult circumstances or simply inexperienced: wet items not put in appropriate bag types causing loss/contamination issuesmobile phones not put in plane mode/switched offcontinuity labels on bags not always properly signed.All of these mistakes are through poor practice rather than malice, and usually by newbies who lack the muscle memory for this stuff.

Experiences of evidence losses in 'cold' cases
Paper files were portrayed as easily mislaid, or perhaps already destroyed under old retention regimes: When investigating a serially convicted child molester, who was continuing to abuse children as recently as 2018, I had cause to go back and review his older cases, to investigate patterns in his offending, such as his modus operandi, his accomplices, etc.But I found almost all records of his prior casescourt files, police files, prison fileshad been destroyed.
Sometimes of course, in historical cases, these materials would have been lawfully destroyed or simply (perhaps understandably) lost in upheavals during the years: Historic murder more than 30 years old.Materials list included exhibits and original statements.Also paper crime reports.Lots of paperwork used to be destroyed after 7 years.A lot also got mislaid during police station closures and when investigations went from paper to digital.This distinction was sometimes drawn between items being 'destroyed' and 'lost', albeit resulting in the same investigative dead-end: Only in cold case investigations of over 30 years old.Some evidence was not correctly packaged, logged or retained.Some exhibits supposed to have been retained had simply been lost, though not officially destroyed.Analysis of exhibits which may have revealed a suspect in an unsolved murder could not be conducted.
Those who had to revisit older, or unsolved 'cold' cases often reported difficulties and confusion: When trying to pull the cold case together to get final justice for the victim it was shambolic (7 years later), various stuff had been destroyed, some retained, no structure or process of destruction versus retention made any sense and no idea why some remained and others didn't.
Several officers commented on the impossibility of re-investigations as 'exhibits had either been destroyed or could not be located limiting any further investigation'.For example: Unsolved murder which occurred some 15 to 20 years prior to the date of the re-investigation.Victims clothing at the time of the re-investigation could not be located in the property systemtherefore vital potential evidence was lost to the investigation.… Case to date is still unsolved.
So despite regular media reports of offenders prosecuted years after their offences, these may represent just the tip of a larger iceberg of cold cases that could be solved: A number of officers recounted frequent negative experiences: 'Cold case exhibits are never where they should be.
Items are regularly lost in archive', with many clearly frustrated at the closing of possible investigative avenues: Tried to find exhibits for a 1985 murder a couple of years ago.No local records, no records of it at the force storage facility.Hand-searched their records and visited the retired exhibits officer.Cannot search the storage facility due to the immense number of exhibits.From crime scene photography, the exhibits would have been full of forensic opportunities not known at the time.Potential to have solved the case.
In one instance the officer had gone to extreme lengths to find materials: The biggest one was a historical homicide from 1985 being reviewed where they thought there would be forensic opportunities.There was absolutely no trace of the exhibits.I checked through all their recordsno record of the exhibit officer's name, no trace anywhere; we went and spoke to the original exhibits officerhe was in a care home and had no memory of it.
Even where (paper or digital) files may have been retained and are located, there can be significant issues with other materials.There was a great deal of discussion about the contamination and poor preservation of evidence, even surprisingly, that: 'Nothing has really gone into the research of how long [exhibit bags] last and whether we're using the right mediums to ensure that preserves that exhibit'.The importance of properly retaining evidence was underlined with reference to poor retention practices and cases going, and staying, undetected: You've got to mothball securely so that, if it needs revisiting, everything possible you could need and has been used and generated is there… We've just moved offices and the bits of stuff you findit's scary… In undetected crimes, that knowledge is lost so quickly from the case and it's so difficult to get it back again because the systems weren't in place.

Weak links: Packaging and storage facilities
From the number of comments alone, packing and labelling (both vital to the integrity of materials, continuity, proving chain of custody and allowing for later relocation) is a real weak link in the chaincausing, or exacerbating retention/ storage issues that may arise later: Exhibit bags incorrectly filled out and it not sealed appropriately.Is often a common mistake.
As a crime manager I often 'walked the floor' finding exhibits under desks, in drawers sometimes not even sealed.
Poorly packaged or not sealed properly or not stored short term in a secure location.I have known of cases in the past where so much evidence has been seized it's not been correctly secured.On many occasions exhibit bags are not signed and dated when handed to the next officer so the continuity of the evidence is hard to establish.
Numerous experiences.Examples includedproductions left in lockers and never submittedincorrectly/incompletely completed production labels and production bookproductions damaged in storage due to production rooms leaking, being crammed full or being droppedproductions left in insecure places, especially larger items… Incorrectly packaged, not double-bagged, bags left unsealed, bags not signed … the list goes on sadly.
Finding officers not wearing gloves and contaminating exhibits.Exhibit bags not being sealed correctly or failed seals due to age.
The problems caused by incorrect packaging were highlighted: Mostly incorrectly packaged by police officers.(Wet cans in a plastic bag, wet gloves in a paper bag, not booked into property store early enough, poor documentation.)Sometimes bags/ boxes not sealed correctly.…The main problem was the inability to examine an item forensically, or examine an item to its full potential due to packaging or storage issues.
Often, however, failures were again attributable to 'systems' failure, resource issues or lack of knowledge: Items getting left behind at desks, or stations, which whilst sealed are not stored properly until found and moved.Lack of Faraday bags for computers, phones and tablets to prevent interference.Lack of working facilities and knowledge to deal with wet exhibits that need to dry.
Inadequate storage facilities and capacity limitations were the most common complaints in survey comments with 10 police interviewees also detailing this as the predominant concern.Contamination of items was brought up by several officers: 'Upon joining a new unit I discovered that exhibits were being stored in an insecure cupboard, hard drives stored alongside drugs that were seeping and a plethora of other equipment all in the same room'.With lack of space making contamination almost impossible to avoid: [W]hilst working on homicide the exhibits were stored from every job in the prep store which was never cleaned down and sometimes exhibits mingled from different jobs.Then comes a request to send exhibits for forensic analysis and the issue could be contamination of other jobs.
One officer reported specifically that: 'the child abuse investigations unit never had a big enough store to cope with the amount of exhibitsyou literally had to squeeze exhibits into places with other evidencethat's crosscontamination … there's holes everywhere…'.
Many storages facilities were characterised as aged, and in dire need of maintenance, with flooding specifically mentioned on several occasions: '[there are] all sorts of problemsinsufficient space, production rooms that flooded with things going missing all the time'.The volumes of material were a common problem: 'The other issue is volumeif you could see the warehouses, you'd see the problems'; 'only problem is where do you store these items?forexample, exhibits with a radioactive halflifewith space, you can store everything properly'.As one officer eloquently put it: I suppose it's like dealing with Primarkwhen you go to Primark, everything's just stacked really high and something will get lost somewhere along the line.If you went to a more high-end store, they've got very few things and everything's meticulously audited.
As the Casey Review highlighted, a lack of, or broken freezer also means lost material, an issue our respondents mentioned: 'The main thing for us is the ability to store the amount of exhibitsfreezer and physical exhibits requiring a huge amount of space'.One officer recounted: 'We had an issue where one of our freezers broke and we lost a lot of long-term exhibits which should have been retained for many years'.Capacity pressures are particularly acute when freezing is required, causing issues when then overloaded: In 2016 I was tasked in conducting a forensic survey of freezers held locally in a police building.It quickly transpired the freezers were not functioning correctly and this impacted on the integrity of the exhibits housed there.The main cause of the problem was that all the freezers were critically overloaded and subsequently the freezers were acting more as storage facilities rather than frozen storage.There were manufacturer's instructions about overloading and essential airflow but this had not been adhered to.Immediate action had to be taken about transferring the exhibits to a long-term storage facility and noting that the exhibits had been subject to a freezethaw-freeze process.

Weak links: Chain of custody issues
In 'live' investigations, with evidence being moved around, police complained that: 'Too often exhibits are removed from exhibits cupboards/cages for enquiry purposes and not returned', with reports of: 'Personal experience of evidence having gone to the wrong place, wrongly labelled, been delayed, stolen or simply lost'.It was also clear that difficulties arose when materials changed hands between different agencies, i.e. between forensic analysts or experts, and the Courts and legal professionals: The Court themselves would regularly lose productionsit's not just a police issue.I certainly remember on more than one occasion, production officers swearing blind and being able to show the signed receipts, to show that a production went to the courthouse but the court would deny point blank that they had ever received it and would then try and blame the police and there would be a bit of a bun fight.
Several officers reported materials going missing when being sent to/from FSPs: 'I was case manager for a case where an outsourced digital forensics company lost a SIM card'.Senior forensic scientists also warn of their inability to re-investigate or re-evaluate cases that they have previously worked upon, because once initial inquiries are complete and materials are returned to the police, they cannot guarantee any chain of custody so should refuse to work further on these cases: The very process of trying to introduce new storage systems or digitising records can also result in losses: 'a new centralised property store system was introduced, store managers unable to account for where items are as the computer records are inaccurate and items have been lost'.The downstream impacts of a dubious chain of custody was well understood to cause problems with subsequent prosecutions: 1 kilo of heroin was sent via internal despatch to office and left on a desk for three days until the person the package was addressed to was next in.Sent by the lab with no continuity as they had finished with it!Cases could be thrown out due to continuity issues or allegations of tampering.

Strengthening weak links
The most obvious solution to issues of capacity and space is to repair existing, or to build new adequate storage capacity: 'the biggest problem was always where to store productions.The police should be looking at building purposebuilt stores'.In addition, technological improvements were suggested: 'It's the technology side that's lacking, from the point of collectionwe're missing a trick there', with many bemoaning the lack of simple solutions like: 'barcodes to speed things up, like you would do at a supermarket or Amazon'.Even with technological advances in place, there is still human fallibility and frailties and time for officers to utilise the technology: Everything should be barcoded, scanned in at the time it's collected, all the way through.People just write it on a spread-sheet…, or they don't.Invariably when it comes down to 'shall we do that?' somebody is shouting that their flat's being broken into and they're in fear for their livesso well we just do that bit.
Many officers spoke of the value of dedicated specialist roles: 'You should have somebody who oversees exhibits, somebody dedicated to the retention and examining of exhibits.That should be standard practice.It would make the continuity issue less of an issue'.But that these specialist roles were rare and exhibits managers rarer still: The exhibit role was always seen as a specialist role… only a select few officers were trained to do that … On every team, we should have had an exhibit manager to supervise the exhibits officers but there wasn't, you were just left to your own devices.
Although specialists were suggested, most often the training of all officers was raised: ' [Training] has to be across the board and it's not happening', particularly of inexperienced officers attending crime scenes: 'It's trainingeducating, educating, educating.They don't get any training on exhibit handling, and these frontline officers, they are the first people at the scene of the crime to secure evidence'.A problem exemplified by a scandal in the news at the time of interview: Everybody should be doing an exhibits course.One of the biggest problems we have at the moment is the initial crime scene integrity.PCs [police constables] just do not understand that they're not to go into a crime scene.You see examples like those two officers who took pictures of those two dead girls.That's not the only example.

More supervision was clearly called for both at the training stage:
Back in the 90s, officers were trained differently … these days you come into the police and you work alongside somebody else with no real police experience.It's quite clear to me that nobody's going to court that often so they're not getting their backside chewed when they haven't acted properly.
But also for more senior officers too: 'At a lower level, there may be some supervision but at a higher level you're expected to know what to do', 'There's lack of supervision at all ranks'.This lack of supervision and experienced officers is acute when cases are being concluded and materials stored: There should be constant supervision but, when a case is concluded, it's the officer's job to deal with those exhibits so that's where the supervision falls away.You're relying on investigating officers at junior rank to deal with retention and disposal of exhibits correctly.That's where it falls down.
Albeit inexperience was not always a factor with an officer witnessing: 'a supervisor failing to seal his exhibits at the scene and then mixing them up back at the station'.
Training is also an issue for the proper understanding of the legal and policy framework.There has been a clear problem with officers understanding the legal requirements for the retention of materials: The CPIA is a piece of law that has been trained out to people but never fully adopted….There is no uniformity across the board in the way these policies are adhered to … There is a piece of law that has to be adhered to … supervisors now don't understand the procedures themselvesit's like the blind leading the blind….It isn't just about the training of the constables but the managers and middle managers, but also the CPSlike the Liam Allen casehow did that case get to court?Although these suggestions focused on changes to police capacities and capabilities, not all issues are due to internal police practices and facilities alone.There are clearly external pressures, and other agencies involved.Furthermore, there are bodies or agencies that could, or should, have a role to play in addressing this issue.

Evidence loss: Falling through regulatory gaps?
The much mis-attributed and maligned cliché 'what gets measured gets managed', might still shed some light on why the problems highlighted in this article persist: no one is taking much notice.As with the provocation to this research, criminal justice agencies appear to either live in ignorance of the problem (it's not being measured), or mistakenly believe that it falls within the remit of some other agency (someone else is managing it).Instances of lost materials are rarely addressed on an aggregate basis, rather than as simply 'one-offs'.Both the Daniel Morgan Independent Panel Report and the 2023 Casey Review repeat longstanding concerns that these issues have been reported on previously, to no avail.
Strengthening the 'weak links' identified (packaging/ facilities; training and supervision; chain of custody safety and recording; and sufficient personnel) requires dedicated resourcing, with time and money that have to be found from already overstretched police budgets.Yet there are also financial and resource ramifications if police are retaining too much material for too long as a result of confusion around the legal and policy framework.'Erring on the side of caution' too often, and retaining materials that could be safely and lawfully disposed of, puts creaking systems under strain unnecessarily, and potentially breaches the Data Protection Act.FSPs, themselves underresourced, are limited in their abilities to address police storage issues, because they have to return materials to forces and then their influence ends.The Forensic Archive also has an extremely limited role given that its remit is (almost) exclusively to warehouse materials from the FSS (so pre-2012; McCartney and Shorter, 2019a).
That it is rare for any external bodies to look into this issue also militates against the necessary resources being dedicated to strengthening the weak links.The Forensic Capability Network (FCN) wrote detailed guidance to support police in interpreting the NPCC Guidelines, which is welcome but the FCN appear to have no further role and the College of Policing have admitted to having no particular interest in the area and believe that their training materials (a 75-minute session) sufficient.The Forensic Science Regulator (FSR) might be assumed to have a role to play here, but narrow interpretations of the parameters of both the Forensic Regulator and the Biometrics and Surveillance Commissioner roles, as well as nomenclature, mean that neither include this issue in their remit.The Biometrics and Surveillance Commissioner in their 2022 annual report, again detailed the problem of 'lost' DNA samples, with 953 reports of police failures to seal DNA sample bags correctly from all but nine police forces.(Biometrics Commissioner, 2023: para.73), as well as 'incomplete forms or sample tube details (253 reported), contamination on swab i.e. hair/staining (177), and sample missing (145)' (para.75).The Commissioner states that they have been in contact with the FSR about these failings, a good example of where an issue falls in a gap between regulators.
FSR documentation, like the College of Policing, refers to 'evidence' or 'exhibits', with the attendant danger of attention being focused exclusively on materials 'used' in proceedings, which may not include other items, e.g.swabs or tapings that have not (yet) been tested or other 'unused' items.The FSR Code of Practice (Forensic Science Regulator, 2023) also needs to ensure that the quality requirements are extended to police storage facilities and not simply 'forensic units'.Indeed, the remit of the FSR over police storage practices and facilities remains unclear, in particular with relation to cold case reviews and miscarriage investigations.Furthermore, paragraph 42.1.6 of the Code states that: Original items/exhibits collected or seized by, or submitted to, forensic units should be returned to the commissioning party or nominee, normally as soon as possible after the FSA is complete and/or a case report is issued, except where: a. they fall within the special provisions, such as being a biohazard, or have other controls stipulated by the commissioning party.
There is a concern that in broad terms this might give police forces or FSPs licence to destroy materials, rather than using biohazard packaging (created for this very reason).This has happened previously when police have destroyed material 'because it had blood on it and so was a biohazard'.
Perhaps it should be expected then that HMICFRS are a 'backstop'?Again, we can find no evidence that HMICFRS undertakes inspections of police storage facilities.Their 'operational assessment' includes the questions: 'How good is the force at investigating crime?' and 'How good is the force at managing serious and organised crime?', but there is no mention of evidence storage and retention, key to both of these tasks.Furthermore, we can find no mention of such issues in inspection reports, or any thematic inspections on this topic, beyond their evaluation of the MPS response to the Daniel Morgan Independent Panel Report.Perhaps, as suggested during an interview: 'If they had an Exhibit Management Commissioner, like they have a Biometrics Commissioner, and someone from that office came out to inspect forces twice a year, then it might happen.Inspection scares everybody'.
While no body or agency appears to have any oversight of police storage, the question then remains: what does happen when things are lost?As we have seen, the CPS have previously been fined by the IOC for losing materials, but the remit of the IOC is changing and fines will no longer be issued to public sector agencies, but instead be replaced with 'reprimands'.The Daniel Morgan Independent Panel (2021: para.1025) found no evidence of enforcement of the Police (Discipline) Regulations 1985 (in force at the time) which defined an offence of damage to police property where an officer has: (a) wilfully or through lack of due care causes any waste, loss or damage to any police property, or (b) fails to report as soon as is reasonably practicable any loss of or damage to any such property issued to, or used by him, or entrusted to his care. 13  The IPCC 14 has previously concluded that 'guidelines are not procedural rules and officers should not therefore be bound by them'.(Independent Police Complaints Commission, 2015: 98).Worryingly then, even were the Independent Office of Police Conduct (IOPC) to investigate a case of a failure to preserve materials, the NPCC 'guidelines' would conceivably be interpreted in a similar fashion.So, there is no penalty for a failure to comply with the CPIA Code of Practice as this can be breached without penalty or disciplinary proceedings, and the NPCC guidance is simply 'guidance'. 15Indeed, the IOPC, in response to an FOI request on investigations undertaken on lost materials, responded exclusively with reports on cases where materials were 'lost' because investigators had failedoften in the early stages of an investigationto seize the material in the first place. 16So 'lost' is interpreted to mean evidence that may have existed, but is now unavailable because of early investigative failures to collect itarguably a different problem (albeit still a serious one).
Although there is a lot of emphasis in policing guidelines (such as the APP mentioned) on the vital importance of both seizing and preserving potential evidence (particularly during the 'golden hour'), IOPC investigations focused on seizure, with no consideration of failure to 'preserve'.This might be because, aside from a police force selfreferral to the IOPC, it appears that the IOPC has not investigated a complaint on evidence loss, probably because complaints must be made within 12 months.The charity Inside Justice tried to complain to the IOPC about one force in which there had been wholesale failures to adhere to proper procedures, resulting in the loss of materials.This complaint was 'disapplied' (not heard) because the action had occurred more than 12 months earlier.But when investigating a potential miscarriage of justice, how could the actions be known about within 12 months, by anybody other than those responsible?The Police Ombudsman for Northern Ireland has a similar 12-month rule; however, the RUC (Complaints etc.) Regulations 2001, section 9 states that the Ombudsman may investigate complaints: [W]here new evidence has come to light which is not evidence which was reasonably available at the time the matter originally occurred, the Ombudsman believes that a member may have committed a criminal offence or behaved in a manner which would justify disciplinary proceedings, and the Ombudsman believes that the matter should be investigated because of the gravity of the matter or the exceptional circumstances.
The failure of the IOPC to investigate individual force failings, compounds the problem nationally: there can be no 'lessons learned' nationally with regard to evidence retrieval, retention and storage when there are no investigations into the issue.
The Courts are also not willing to view loss of evidence as an 'abuse of process' as a possible deterrence measure.The question of whether criminal trials can proceed when material is missing was recently considered in R v. ANP [2022] EWCA Crim 1111, when the prosecution appealed the termination of a rape trial, where the judge had been persuaded that when all the physical material was lost before scientific analysis (as had occurred in this case), there was an 'evidential vacuum' and continuing the trial would be an abuse of process.Although the appeal judges were 'slow' to interfere with the decision and agreed that: 'There was certainly an absence of some evidence, which should have been available' (para.24), they allowed the prosecution appeal, but made clear that: 'there must be a case-specific assessment which focuses on the importance of the missing evidence in the context of the case, and the nature and extent of any prejudice caused to the accused by its loss' (para.27).Thus, this trial could continue, but it will depend upon the circumstances in other cases, so the Courts may not consider lost evidence an 'abuse of process'.

Conclusion
The seizure, safe handling and secure storage of evidence during criminal investigations is pivotal to the successful detection and prosecution of offences.The safe retention of materials after an investigation closes, even postconviction, is also critical both to the ability of the appellate system to overturn wrongful convictions and for 'cold cases' to be reviewed.The CCRC do not (publicly) acknowledge that loss of materials is impacting their work, and the Courts do not view the loss of materials as sufficient reason for a trial to be discontinued or an appeal to be heard.The number of cases being dropped pretrial by the CPS because of lost material is not diminishing, and although the CPS themselves have fallen foul of the Data Protection Act and been fined heavily, there is little evidence of efforts to pressure the police to strengthen the weak links in chains of custody between the two agencies.Yet inefficiencies and ineffectiveness in the criminal justice system are headline news on an almost daily basis and the frequency of failed investigations and prosecutions is exacerbated by lost materials.Those claiming a miscarriage of justice are unable to successfully appeal because investigations cannot prove (either way) whether there has in fact been a wrongful conviction, and cold cases remain unsolved.
Despite periodic high-profile instances of failures to ensure the integrity and retention of evidence, there is a reticence to admit to evidence being lost, and in particular to consider the issue on an aggregate rather than a case-by-case basis.Before any issue is deemed worthy of resources, raising the 'visibility' of the problem with accessible data on the scale of the problem must be a priority prior to addressing regulatory gaps.This research attempted to gauge the loss of police investigative materials and determine reasons for such losses, in an effort to locate potential solutions.It is clear that practical issues such as the storage facilities themselves need proper resourcing, with adequate training and supervision of staff, and ideally, specialised roles filled with sufficient expert personnel.
'Forensic regulation' could not be said to have any (effective) oversight of this area, the College of Policing has no apparent interest and the NPCC and FCN may have written national guidelines but take little role in overseeing their implementation.HMICFRS do not include inspections of 'stores' and the IOPC '12 month' rule on complaints precludes almost any reports relating to lost evidence.Each of these agencies could play a role; most obviously HMICFRS should include police stores in their inspections and the Forensic Regulators Codes of Practice should include specific provisions regarding the safe storage and retention of forensic materials.This is an issue that need not be intractable, but requires public acknowledgement and accessible data, resourcing of solutions, and accountability and oversight mechanisms agreed upon between the many agencies involved.
which may result in a narrow focus on 'used' material.We therefore use the term 'material' to preclude a narrow focus on 'exhibits' and instead encompass any material gathered during a criminal investigation (whether 'used' or 'unused').We also focus on 'investigative' materials, i.e. material that the police have seized or gathered as part of an investigation, not police 'property' more widely construed as anything that the police may end up holding that is the property of a member of the public or organisation, such as items taken from arrestees or lost property.2. In general the terms 'storage' and 'retention' can ordinarily be used interchangeably, albeit 'retention' tends to refer to longer-term storage after an investigation is closed.3.In general, we refer to material being 'lost', which could encompass it being incorrectly labelled or packaged (so making integrity and reliability dubious) destroyed, contaminated or otherwise no longer accessible or useful.4. CCRC Stakeholder Forum meeting, London, May 2019. 5. Trial transcripts can be lawfully destroyed after 5 years.6.We concede that the MPS in many respects can be considered an 'outlier' and many other forces do not have the same issues and not on the same scale, but data on the MPS is easier to obtain and they receive greater attention in this, as in many other areas.7.In June 2019, the MPS streamlined its recording system from 61 standalone databases to a centralised system, which should (in theory?) mean that there is improved record-keeping of materials.8. Clearly this organisation is not the 'police', but the interaction and exchange of evidence between them and the police, we would argue, make relevant issues around their loss of evidence too.Albeit we do not focus upon the CPS in our research and they require separate focused research of their own, which we would encourage others to undertake.9. Section 22 Metropolitan Police General Orders, MPS107540001, pp. 132-133, paras 165-166, 1982. 10.Research found three articles: Badeaux (2010), Jones (2005) and Strom et al. (2011).Strom et al. looked at a sample of state and local law enforcement agencies and found fewer than half had a policy for retaining biological material from convicted offenders.11.A rare example of an 'official' report looked at forensic evidence, and forensic DNA sample retention in laboratories (Steadman, 2000).This research was repeated in 2001 (Steadman, 2002) 14.The Independent Police Complaints Commission (IPCC) is the former name of the Independent Office for Police Conduct (IOPC), the major 'disciplinary' body for police.15.In other jurisdictions, such as some states in the United States, a failure to retain evidence may afford a ground of appeal.This is not the case in England and Wales.16.For example, in the investigations into cases concerning Sean Rigg, Poppi Worthington, Rachel Whitear, Sean Lubbock and Yassar Yuqab, the focus was failure to seize or preserve potential evidence.
With rape cases maybe 10 or 12 years old.It's more the investigative paperwork around it which is just very difficult to traceextracts we're trying to get re-analysedwe end up going to the FSP saying 'what have you got?' because we don't know what exists.Our management internally has been very poor, again probably due to the fact that computer systems have completely changed and we just haven't got the records we should have about (a) what's been taken, and (b) what work has been conducted in the interim and the results that that has generated.

I
put slides containing sperm from a rape case in the post and off it goes back to the police.I will never know what happens next so I will never work with that evidence again as who knows what happened to it.(Personalcommunication,  September 2022) . 12. Biological and Evidence Laws by State: 2021 Official Guide.Assembled by University of North Carolina School of Law's Pro Bono Program available at: https://home.iape.org/resourcesPages/IAPE_Downloads/DNA/Bio_Evidence_Statutes_ by_State.pdf.13.Police property presumably is interpreted here as property purchased/owned by the force, which is considered differently from investigative materials.Regulation 4(1), Schedule 1, The Discipline Code, The Police (Discipline) Regulations 1985, paragraph 12(a), (b).Available at: www.legislation.gov.uk/uksi/1985/518/pdfs/uksi_19850518_en.pdf(accessed 13 April 2023).