An autopsy determined that the fingers had been severed before his death. That, and not being able to identify and catch the killer, apparently was too much for Brooks to take.

Mr. Brooks, a highly regarded investigator, took the death of the precocious, brown-eyed boy unusually hard.

After supervisors and colleagues became aware that it was affecting his work, he took a four-week leave and began intensive therapy sessions with Dr. Ronald Cantor, whom he was referred to by a Chicago Police Department psychologist.

At the start of these sessions, according to Dr. Cantor, Brooks openly spoke of his suicidal feelings and said he was haunted by dreams of the young boy screaming in agony.

After twenty therapy sessions over a four-week period, Dr. Cantor approved of the detective's return to his assignment in the homicide unit. Mr. Brooks by all accounts functioned properly and continued to handle and solve several new homicide cases. He told friends that his nightmares were gone. Known as "Jumpin' John" because of his go get'em attitude, Mr. Brooks even continued his ultimately unsuccessful pursuit of the killer of Bobby Smathers.

But sometime during the cold Chicago winter something apparently changed. On March 13-which would have been the thirteenth birthday celebrated by the Smathers boy-Mr. Brooks sat in his favorite chair in the den where he liked to write poems as a distraction from his job as a homicide detective. He'd taken at least two tablets of Percocet he had left over from treatment of a back injury the year before. He wrote a single line in his poetry notebook. Then he put the barrel of his .38 Special into his mouth and pulled the trigger. He was found by his wife when she came home from work.

The death of Mir. Brooks left family and friends bereaved and full of questions. What could they have done? What were the signs they had missed? Cantor shook his head wistfully when asked during an interview if there were answers for these troubling questions.

"The mind is a funny, unpredictable and sometimes terrible thing," the soft-spoken psychologist said in his office. "I thought that John had come very far with me. But, obviously, we did not come far enough." Mr. Brooks and whatever it was that haunted him remain an enigma. Even his last message is a puzzle. The line he wrote on the pad offered little in the way of insight into what caused him to turn his gun on himself. "Through the pale door," were his last written words. The line was not original. Mr. Brooks borrowed it from Edgar Allan Poe. In his poem "The Haunted Palace," which originally appeared in one of Poe's best-known stories, "The Fall of the House of Usher," Poe wrote:

While like a ghastly rapid river, Through the pale door A hideous throng rush out forever And laugh-but smile no more The meaning of those words to Mr. Brooks is unclear but they certainly carry the melancholy incumbent in his final act.