Then, on April 30, 1970, when he was 20, Kroll drove his car, at a low speed, into another teenage girl. This one was 13 and she was walking in a city park. He dragged her into the woods, slashed her neck, scalp and forehead with a penknife, with such ferocity that the blade broke off. He sexually abused her. He beat her nearly to death with a tree limb. When police arrested him, he acknowledged chasing and cutting a 15-year-old girl a few months earlier, a case that had been unsolved.
The investigation was unsettling. Police found that Kroll kept a half-dozen six-inch wooden dowels in his bed. Some had girls' names on them. He had lain on top of them so often he had a callus on his belly.
"His behavior could be quite bizarre and potentially dangerous," a state psychologist wrote. "The patient apparently derives sexual pleasure by torturing his young victims."
Kroll did eight years.
Six of those were spent at a state mental institution. Psychologists, who found him to be both sane and of "average intelligence," didn't think it did much good.
