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Using Mobile Device Data in the Interview Room

If you’ve been following this column for some time, you know that mobile devices are indisputably excellent sources of evidence in criminal investigations. However, there’s another way their data may be useful: during the interview process with victims of trauma.

The Force Science Institute has shown through numerous studies that memories, following a psychologically traumatic event, can be distorted, misremembered, or altogether blocked.

In a 2010 article, the Institute referred to research that had showed how -- contrary to the belief that many people have, that memory is an accurate playback of events -- the brain could alter memories, both as it records events and also as it recalls them.


  • Details can be fuzzy, overemphasized, or out of place in the timeline, even wrong altogether, as the brain seeks to interpret the inputs.
  • Memories can (often unbeknownst to the rememberer) change along with beliefs about what happened.
  • People can experience someone else’s memories as their own.
  • What might have happened or what a person feels they should remember often become “memories.”
  • Easily recalled memories are often mistaken for accurate or complete memories.


How mobile device data helps the interview process

The Force Science Institute describes a technique known as “cognitive interviewing,” in which investigators ask just a few open-ended questions that foster a free-flowing narrative. The technique encourages memory recall, rather than confrontation or defensiveness.

Thus, if police officers involved in traumatic incidents, such as officer involved shootings (OIS), can benefit from this style of interview, it stands to reason that so can crime victims. And that’s where mobile device evidence can come into play.

Because the interview technique allows investigators to ask follow-up questions to clarify confusion, you can use the data from the victim’s or even a suspect’s mobile device to help stimulate his or her memory.

When helping rape victims, for example, rebuild their memories of one or more assaults, you might start by building a calendar. “Was it before your birthday or after?” and “Was it before or after spring break?” are examples of these types of questions.

As the time frame becomes narrower, you could refer to data you gleaned from the victim’s device, such as location data from trips they took or specific places -- whether in a community or within one building -- they visited around the suspected time of attack. Images or video may support this information.

Content from emails or text messages, too, can help the victim remember particulars. This may take the form of conversations about plans the victim was making, social media posts about his or her activities, or evidence related to the attack, such as threats or an argument. It may also be as simple as asking whether the victim recalls receiving and/or sending messages.

Analytical data, too, can come into play. You may ask a victim or suspect about the strength of his or her associations with particular people, or the frequency with which they communicated via phone, text message, chat, or other media. It’s possible that this could reveal additional suspects or witnesses.

This process also helps to authenticate evidence. The victim who recalls sending or receiving messages, taking pictures or videos, or otherwise recording the evidence shows that the device was in his/her control at the time.

When using mobile device evidence for cognitive interviewing, remember to keep your questions open-ended. Even if text messages or a location pattern seem to paint a clear theory about a case, how you perceive their intent may be very different from how a victim perceives it. Stay disciplined in your questioning to ensure you are covering all possibilities of how a crime came to occur.

Can you use video?

The use of non-video content doesn’t have quite the same impact as videos do, which is to shock the mind into remembering the incident. Cognitive interviewing does allow for the use of a walk-through or video to help place the interviewee back in the context of the encounter; this method has been used with success in OIS investigations.

With victims, it may be that video is available of the attack. However, any type of content, from video to abusive text messages or emails, can trigger trauma reactions, especially in emotionally fragile victims. For example, the incident may have been recorded either by the suspect or by witnesses who failed to help.

Victims block frightening memories to protect their emotional well-being, so if your use of video or other content unblocks them, you may unleash an emotional reaction you weren’t expecting. Consider having someone else in the room, such as a victim advocate, to help.

(Loved ones are not always ideal. Victims may refrain from saying everything that may be relevant, out of a sense of shame or to protect their loved one’s feelings.)

If you do opt to use video, remember that it has other limitations. For one, you cannot show any child pornography footage either to victims or to adults.

Furthermore, as the Force Science Institute has noted, videos are not fully contextual and may not represent the incident’s totality. They can also distort physical realities such as distance or light levels, so they may not accurately represent what the victim perceived.

Used judiciously during the cognitive interviewing process, mobile device data can be extremely useful in helping victims to remember incidents, proving or disproving alibis, narrowing timelines, and identifying additional suspects, victims, or witnesses.

Understand the data you can obtain from smartphones and other mobile devices, know how it can support your case, and build it into your overall interview strategy for potentially greater success in your investigations.


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