The Forensic Artist

In a grocery shop a customer suddenly threatens the cashier with a knife. She should give him all the money in the till. The cashier does not react immediately and the attacker becomes nervous. He stabs the cashier and seriously injures her. He runs without taking any money. The attacker is unknown. There is, however, a witness statement about his appearance. The description is not very useful though: male, 20 to 30 years old, approx. 175cm to 180cm tall, dark hair and dark eyes. But the witness claims he would definitely be able to recognize the attacker in a photo, and moreover – he can give a detailed description of the attacker. He knows exactly what he looked like.