The importance of instructing a Defence Expert in indecent images Investigations

Roger Sahota, an acknowledged authority in this area, explains why it is essential that the technical evidence relied on by the police and CPS should be properly scrutinised.

In any indecent images investigation the critical evidence that will largely determine the outcome of a case will be the Crown’s expert forensics examiners report.

Commissioned by the police at the pre-charge investigation stage, the report will be compiled by a police officer from the hi-tech crime unit or independent forensics expert.  The identity of the expert will be important – police officers who are asked to produce these reports can often be challenged on grounds of bias or because they do not meet the definition of an expert.

The report will contain an analysis based on an electronic audit of what is recovered from a hard drive, RAM or digital storage seized by police during the searches of property connected to a suspect. Importantly, the report will not just confirm if illegal material has been found. It should also identify when, where and by whom the device was used at the time any material was downloaded or viewed.

Surprisingly, the work commissioned by the police is often riddled with errors. Our research suggests that, for example, 40% all the images located in the police data base are incorrectly graded according to the sentencing guidelines matrix.

Moreover, with the impact of swingeing cuts to police budgets, many police forces are limiting the scope of the work they ask their experts to conduct in order to save costs.

Cutting corners in this way means that there are often gaps or errors in the contents of the report produced by the prosecution because for example a full review of the entire contents of a hard drive may not be executed.

As a starting point, defence lawyers should therefore never assume that the contents of any report relied on by the Crown are complete and reliable. Nor should they assume that the Crown’s experts have correctly applied the law to the facts of a case.

Frequently, we have found that the reports relied on in cases we have been instructed in do not contain sufficient information so as to satisfy the legal test for the prosecution of the two main offences that arise i.e. either the possession or the making of indecent images.

To prove the offence of making (the legal term which includes the act of downloading) for example the onus is on the Crown to show that each individual file discovered was deliberately downloaded with knowledge of its contents. In other words, the Prosecution must demonstrate how each individual picture/movie/thumbnail/cached image was downloaded and by whom. Often it will be difficult to establish this (depending on where in the hard drive the images or video files were found.)

To prove the offence of possession of extreme or indecent images, the prosecutor must produce evidence that material found on a computer had been viewed. Any possibility that the illegal data comprises e.g. pictures from the cached section of a web page that may not been viewed by the user has to be eliminated. Once again, depending on the location of the  suspected images or video files, the Crown may struggle to prove this fact.

Without the benefit of a defence expert’s report, defence lawyers may not be able to take advantage of a range of technical defences that regularly arise in these types of cases. 

Contact Roger Sahota at our London office if you have a query concerning an indecent images or computer related police investigation.