'Jigsaw' E-fit system helps ensure that the face fits

Researchers from the Face Processing Research Group have pioneered a new system of compiling E-fits of criminal suspects.

The group, based at the University of Leicester, the Open University and University of Westminster, says the technique could help police identify criminals more accurately.

Researchers are also investigating the benefits of using the evidence of multiple witnesses to create a closer likeness.

Richard Kemp, senior lecturer in forensic psychology at Leicester, said the present system gave no context-enriching visual clues. "At the moment, the witness does not see anything until the final E-fit is produced. Under the old photofit system, witnesses were offered selections of eyes, for example, but this did not provide any context.

" The preliminary findings suggest that by involving the witness in the process more richly, a better fit can be made."

The new "jigsaw" method seeks to modify the existing system used by most police forces by reducing to a minimum the memory interference that distorts a witness's vision of a suspect.

Instead of compiling an E-fit on the basis of a complete all-embracing description that is then fed into a computer, the refined process will build up an image piece by piece, using only descriptions that the witness has supplied.

Dr Kemp said: "Under the current E-fit system, as a witness gives a description of, say, the eyes, the computer chooses the best set of eyes for you, and so on. The witness does not see the face until it is completed.

"What we are saying is that you can improve things by allowing witnesses to watch the face build up. However, because it is important that the features are always seen as part of a face, a cartoon outline and features are used to replace those elements that have yet to be described."

Dr Kemp said the technique, developed in conjunction with Jim Turner of the University of Westminster, has advantages because of growing knowledge about the way memory works.

"Our memories are not photographic processes. People distort things, even forget things. Psychologists have been working with the police to try to improve those memory processes. Changing the way police conduct interviews to elicit information for the E-fits aims to get the best information possible out of the witness," he said.