As a digital forensic expert witness working in criminal cases involving analysing the content of mobile phones, I can understand the concerns that arose from the recent news of police demanding access to phones belonging to complainants. These concerns are particularly apparent in cases involving alleged rape or sexual offences, as it is feared people may be deterred from reporting such cases. What is not discussed – and what must be made clear – is exactly how that evidence is handled.,

First, even if gathered as evidence, a complainant’s phone is not always examined and will only be considered for examination if it is reasonable to do so. Second, where a phone is examined, only relevant information from it is disclosed.

What is relevant information? It be that the complainant informs the police they received messages from the accused discussing an alleged assault, hence both the accused (the defendant) and the complainant phones may be examined to review those messages. It may also be that the defendant, in reply to an accusation, states that there is information stored on the phones which proves they have not committed the offence. What is of primary importance is that any investigation must be fair for both the complainant and defendant. Sometimes, though not always, ensuring this results in the need to review the content of one or both parties’ phones.

Complainants, particularly in rape and sexual offence cases, may have concerns that the private content of their phones is not shared with the defendant. Having worked as a defence expert witness in such cases, I can assure you that defendants and defence lawyers are simply not allowed access to the full content of a complainant’s phone. They are provided with limited disclosure which meets strict criteria deeming it relevant.

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Where concerns are raised by the defence that, for example, the police may have missed some evidence or that the evidence provided by police is presented out of context, then the defence team are rightly permitted to instruct their own expert to report on the relevant information. It is this expert who may be securely provided with the content of the phones, but they too must adhere to strict rules when assessing this information, including the Criminal Procedure Rules.

The key throughout is that any investigation and disclosure by police and experts must be relevant; that is, it must relate to the alleged offence or the circumstance of it.

But this is where it becomes more complex. It is sometimes not possible to provide, at the outset, the parameters of what types of information that may be present on a phone, since every phone and case is different and the way people use their phones is individual to them. Until a phone is examined and the information found, it is unknown what relevant evidence is available.

It is often assumed this process is simple; that access can be restricted to only reviewing a small list of items, for example just the messages between the defendant and complainant. However, in my experience, it is often more complex and such strict criteria may result in missed relevant information which may provide supportive evidence of the offence or exonerate the defendant.

Relevant phone evidence can be present in many types of information. For example, the defendant may have sent messages to other people via text discussing the alleged offence, or there may be additional message evidence not stored in the message history but present in the images on the phone if the defendant frequently captures screenshots. The complainant in a robbery, say, may capture photographs of items after the point at which they alleged the objects were stolen. And location-based evidence on a phone may determine it was located 30 miles away from the suggested location at the time of an alleged offence.

​For all of these, it may not be initially obvious why the police or expert may wish to download and review the data, even though they are all potentially relevant depending on the context of the case. Such a review of the phone is needed so that the evidence can be reported in order to provide an unbiased representation of the relevant evidence for both parties, and ensure justice is conducted fairly.

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The other obvious question from this is: what is not relevant? This question is much easier to answer – it is anything not relate to the offence.