Marty Kolakowski doesn't fancy himself a gifted writer. But the nerdy 25-year-old has a knack for creating believable characters. Among his favorites is Melissa, a cute high school freshman who spends her evenings listening to Creed and Dream Theater--and chatting about sex online with adult men. Her mom, Melissa tells these men, is so strict that she is thinking of moving in with her stepsister, a party girl who shacks up with a boyfriend.
Kolakowski, an investigator for the Wayne County sheriff's department in Detroit, went online with the screen name Melissa83 about a year ago as bait for pedophiles who,...