Three men are detained following a bomb threat called into a city subway system. The first, 24-year-old Nolan, is a thin architect who wears glasses. The second, 34-year-old Luke, is an ex-rugby player who now works construction. The last is 23-year-old Asher, an overweight video game store owner. The investigator on the case takes one look at the three men and singles out Luke for questioning because he looks like the type who would commit a crime. What kind of theory is this investigator using to reach his conclusion?

A. hormonal


B. weather


C. chemical


D. body type