CSI: Can't Seem to Investigate - Police Often Lose Vital Case Evidence

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13 October, 2023

Craig MacKenzie

A new study by Professor Carole McCartney of the University of Leicester has highlighted police handling of materials gathered to support criminal prosecutions.

Professor McCartney found:

CPS data indicate 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.

Those cases included:

  • 42 homicides (1.12% of the total homicides prosecuted in that period),
  • 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 collated last year- September 2021 to September 2022 - showing 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.

There is also an inherent risk that evidence vital to establishing the innocence of someone is also being lost.

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's 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 convicted of the 1989 rape and a series of other serious sexual offences committed between 1998 and 2010, when the DNA sample was 'missing'.

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: 'Robbery - weapons, balaclavas, gloves. Rape - defendant's mobile telephone. Murder - policy file, original records of alternative suspect enquiries. In many cases - police pocket notebooks.

Whether attributable to 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 [X] Police in connection with the case. Eventually told it had been destroyed accidentally.


Professor McCartney's research now provides compelling evidence that there are serious problems relating to handling case materials that can prejudice prosecutions and potentially lead to further miscarriages of justice.

As a firm, we have studied this research in detail and will utilise the findings to secure the best possible outcomes where the loss of evidence disadvantages a client. This research illustrates that the problem is never just unique to one single case but represents a negligent and cavalier attitude to legal duties entrusted to the police.

How can Forbes Solicitors help?

Our Criminal Defence Solicitors know how to deal with lost evidence cases. Legal arguments can be made on your behalf that will stop a prosecution in its tracks.

If we establish that the loss was due to a serious fault on the part of the prosecution and that fairness cannot be restored through the trial process. In that case, a Judge has the discretion to stay (end) the prosecution as an abuse of process.

We ensure we keep up to date with any changes in legislation and case law so that we are always best placed to advise you properly. If you want to discuss any aspect of your case, don't hesitate to contact Craig MacKenzie, Partner and Head of the High-Profile & Private Crime Division.

For more information contact Craig MacKenzie in our Crime department via email or phone on 01772 220 022. Alternatively send any question through to Forbes Solicitors via our online Contact Form.

Learn more about our Crime department here

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