It is a familiar scene-the television detective sits at his paper-strewn

desk, tie askew and head in hands, bemoaning the fact that he has no sus-

pects in his murder case. In reality, however, the investigation of most

“whodunit” crimes involves the exact opposite problem-too many suspects. This is somewhat unexpected but follows from the nature of the investiga-

tive process. The majority of homicide victims are killed by someone they

have a relationship with. So the police detective typically works outward from

the victim, looking at family members, friends, business associates, neigh-

bors, and so forth.