FACES 4.0 Lesson Plan

Police Use of Suspect Composites 

In many crimes, the suspect is someone who is known to the victim or witness. In crimes where the suspect is not known, the first step in an investigation will be to obtain a description from the witness to help identify the suspect. 

A preliminary suspect description will normally be obtained and documented by the officer attending the scene of the crime. That description may be further developed in an interview or series of interviews with the witness conducted by the investigator assigned to the case. 

The suspect may be identified by having the witness review mugshots of persons who have previously been arrested. If the witness cannot positively identify anyone in the mugshot book, and the police do not have another obvious suspect in mind, police may work with the witness to create a composite – a visual representation of the suspect – either through a traditional forensic sketch artist or through the use of facial composite technology. 

The composite can be used internally by the police agency to determine whether other investigators recognize the suspect as a prior offender or a person of interest (that is, a person questioned in connection with a crime but not arrested or charged). Depending on the nature and the circumstance of the crime, the police may also use the composite to enlist the public’s help in identifying the suspect. The police may release the composite to local media together with a written description of the suspect and other information that can help encourage people to come forward to the police with possible leads. 

The FACES software that students will use during this lesson is an educational version of a technology that is currently being used by thousands of police agencies around the world. FACES was designed to allow suspect composites to be developed by police investigators who, previously, had to rely on forensic sketch artists to do this work. Composites can therefore be developed more quickly and cost-effectively, and used to solve a larger number of cases. 

Further, because FACES generates photo-like composites they can be used to carry out an electronic search for suspects. A growing number of police agencies are converting their mugshot photos to digital files and creating mugshot databases. Using facial recognition technology, FACES composites can be used as a query to search these databases and retrieve possible matches. The matching mugshots can then be viewed by the witness to determine whether a positive identification can be made. 

One of the goals of this lesson is for students to have the opportunity to go through a process similar to the one investigators use to interview a witness, obtain a physical description of the suspect, and develop a composite. 

A witness’s ability to recall and describe a suspect’s appearance can be enhanced through interview techniques. It is important for the witness to be relaxed and for the interview to be conducted without interruption or distraction. Some interview suggestions are outlined in the lab procedures below. 

Police will often also use a “cognitive” interview approach to improve memory recall. The cognitive approach takes the witness back to the day of the incident – or even the day before the incident – asking the witness to describe what was happening and what they were doing, bringing them gradually up to the time of the criminal incident. The interviewer may ask questions such as what the scene looked like, what it smelled like, encouraging the witness to relive the incident, and bring the suspect back to mind clearly and vividly before asking about general physical characteristics of the suspect and, finally, specific facial features. 

The observation game can help build memory, recall and composite skills. You can play at different levels from 5 (most challenging) to 1 (recommended for beginners). 

To start, click on the observation icon and choose a level. A composite will appear briefly in the left hand area, then disappear. Try to recreate the composite by choosing from the elements in the right hand area. When you’re done, click on the exercise icon again to compare your result.

The police version of FACES also generates a unique biometric alphanumeric code (BAC) for each composite that, when entered into the software, recreates the image, exact in every detail. The code, rather than the actual composite, can be transmitted between police agencies, giving them greater security when sharing composites for sensitive investigations. This code function is not available on the educational version.