Why Do Investigators Ask Suspects to Demonstrate What Happened?

By Murder Book Editorial TeamPublished by Gungrounds, the studio making Murder BookPublished 3 October 2026Updated 3 October 2026

Investigators sometimes ask a suspect or witness to physically show what happened rather than just describe it. The reason is that demonstrating an action, drawing a scene or sketching a layout requires a different kind of memory retrieval than verbal narration alone. Research led by Aldert Vrij and colleagues at the University of Portsmouth has found that asking people to draw or enact what they experienced can elicit more information and, in some cases, produce clearer differences between truthful and deceptive accounts. The technique does not prove that someone is lying. It adds a channel of information that verbal questioning alone may miss, and it can reveal inconsistencies that an interviewer would not otherwise notice.

Key takeaways

Asking suspects to demonstrate, draw or sketch what happened requires spatial and visual memory that is difficult to fabricate.
A 2010 study found that 80% of truth tellers but only 13% of liars included a key person in their drawings, allowing 80% correct classification.
Switching between verbal and visual report modes can expose inconsistencies in deceptive accounts.
The technique works because liars tend to prepare verbal scripts but not spatial or visual details.
No single technique reliably proves deception. Drawing and demonstration add information, not certainty.

Why do investigators ask suspects to show what happened?

Most people who prepare a false account focus on the verbal narrative: what they will say happened, in what order and with what details. They rehearse words. What they typically do not rehearse is a spatial layout, a physical sequence of movements or the visual perspective from a particular position.

When an investigator asks "Can you draw me the room?" or "Show me how you were standing," the interviewee has to shift from a verbal mode to a spatial or physical one. For a truth teller, this is manageable because genuine memories contain perceptual details, spatial relationships and embodied sensations. For a liar, the shift is harder because the fabricated account may lack these dimensions entirely.

This logic connects to the cognitive load approach: lying is mentally demanding, and adding an unfamiliar task increases that demand disproportionately for someone who is fabricating.

What does the research show about drawings?

The landmark 2010 study

Vrij, Leal, Mann, Warmelink, Granhag and Fisher published a study in Applied Cognitive Psychology in 2010 that tested whether asking people to draw a scene could help detect deception. The study involved 31 participants with police and military backgrounds who were sent on a mission to collect a package from another agent at a specific location.

Truth tellers actually carried out the mission. Liars were given details about the mission but did not go to the location. Both groups were asked to describe the location verbally and to draw it.

The key finding was striking: 80% of truth tellers included the agent in their drawing, compared with only 13% of liars. Based on this single factor, the researchers could correctly classify 80% of participants. Liars drew the location but tended to omit the person they claimed to have met, presumably because they had no visual memory of someone who was never there.

Sketch drawing and inconsistency

Leins, Fisher and Vrij investigated whether combining sketch drawing with verbal questioning could expose inconsistencies in deceptive accounts. In one experiment, 80 participants reported truthfully or deceptively about a lunch date. They sketched the layout of a restaurant and then answered spatial questions about objects in it. In a second experiment, 34 participants answered spatial questions and then sketched a room.

Liars were rated as less consistent between their verbal answers and their drawings than truth tellers. Up to 80% of truth tellers and 70% of liars were correctly classified. The researchers suggested that switching between report modes, from verbal to visual or vice versa, reveals gaps in fabricated accounts that a purely verbal interview might not expose.

Sketching while narrating

More recent research has examined what happens when interviewees sketch while they talk rather than doing the two tasks separately. Studies by Vrij and colleagues found that sketching while narrating elicited more information overall, particularly spatial and location details. Truth tellers reported more information than liars, and the combination of narrating and sketching produced more veracity differences than a standard free recall.

This approach has also been tested in interpreter-based interviews, where language barriers complicate verbal communication. Drawing provides a channel of information that does not depend entirely on spoken language.

Why does this technique work?

The effectiveness of drawing and demonstration rests on several related principles:

Liars prepare words, not images. A person who fabricates a verbal account rarely rehearses the spatial layout, the relative positions of objects or the visual perspective from a particular point in the room. When asked to draw, they must construct these details on the spot.
Spatial memory is hard to fake convincingly. Real memories of places include perceptual details, relative distances, spatial relationships and the embodied sense of having been somewhere. Fabricated accounts tend to lack this richness.
Switching modes exposes inconsistencies. A verbal account and a drawing are two different representations of the same event. If both come from genuine memory, they should be broadly consistent. If one or both are fabricated, the inconsistencies are harder to hide because the liar must maintain coherence across two different formats.

What are the limits?

Like all interview techniques, drawing and demonstration have important caveats:

Familiarity can close the gap. If a liar has visited the location they are lying about, they may have genuine spatial memories to draw on. The technique is strongest when the liar's account is entirely fabricated. Why do investigators ask unexpected questions? discusses a similar limit.
Not all events have a spatial component. The technique works best for events that took place in a specific physical location. Abstract events, emotional states or conversations without a clear spatial setting may not benefit from drawing.
Accuracy is not certain. Even the 80% classification rate in the 2010 study means that one in five people would be misclassified. Can you actually tell when someone is lying? reviews the broader research on detection accuracy.
The technique reveals differences, not guilt. An inconsistency between a verbal account and a drawing might indicate deception, but it might also indicate poor spatial memory, confusion, anxiety or simply that the person was not paying attention to their surroundings at the time.

How does demonstration compare with other cognitive techniques?

Drawing is part of a family of interview strategies that increase the cognitive demands on the interviewee. Others include asking someone to tell a story backwards, asking unanticipated questions and requesting verifiable details. Each adds a different kind of demand: reverse order disrupts rehearsed chronology, unexpected questions test preparedness, verifiable details test willingness to offer checkable information, and drawing tests spatial and visual memory.

Vrij, Fisher and Blank's 2017 meta-analysis of cognitive credibility assessment approaches found that these methods generally improved accuracy compared with standard interviews, though accuracy rates varied across studies and remained well short of certainty.

How does this relate to Murder Book?

Murder Book is an upcoming narrative interrogation game from Gungrounds, an independent studio in Zagreb, Croatia. Development screenshots show an evidence board that links statements together, such as "I NEVER met her!" connected to a fabricated description of a weapon. The game's technique menu includes Demonstration alongside options like Baiting and Confrontation.

The research behind drawing and demonstration techniques connects directly to this mechanic. In real investigations, asking a suspect to show rather than tell can reveal whether their account has the spatial and perceptual depth of genuine experience. In Murder Book, players look for the same kind of gap: does the suspect's story have the texture of something lived, or does it feel constructed? The game treats these observations as reasons to probe further, not as verdicts, which matches the research position that no single sign reliably proves deception.

Murder Book is in development for PC (Steam) and mobile, with release currently planned for the end of Q2 2027.