Matching profiles of masked perpetrators: a pilot study

Seventeen male volunteers were photographed laterally with and without a tight-fitting balaclava. We then matched these photographs in blind trials. The matches were performed in two separate trials: as side-by-side comparisons, and by using superimposition. In both trials we graded the matches as good, possible and no fit. We found a very high true identification rate of 94% using superimposition, i.e. whether a match judged as good was in fact the correct match. The correct exclusion rate was also high, 94%, when using superimposition, i.e. when no match was found this was in fact correct. However, even though we were often correct in judging the best fit, we often had several possible matches for each case, which means that comparing profiles is not very selective. As such, using superimposition to compare the profile of a masked perpetrator with lateral photos of one or more suspects may indicate the possible matches, and perhaps even the best match, which may be helpful in police investigations, but it would not carry enough weight to be used as evidence per se. This study only focused on the profile. Future studies will use surface laser scans to analyse congruence between masked and unmasked subjects using the whole head.