People sometimes said that he had looked evil squarely in the eye, but Patrick Kennedy, the towering Milwaukee police detective who got serial killer Jeffrey Dahmer to talk about his crimes, saw it another way.

"I can't say that I really did, because when I looked at Jeffrey Dahmer, what surprised me the most during the six weeks I talked to him was how very much like you and me he really was," Kennedy said in a recent interview for "The Jeffrey Dahmer Files," a documentary featuring Kennedy and others in the Dahmer case.

Kennedy, 59, died Thursday after suffering an apparent heart attack, his family said.

In the years after the case, Kennedy took early retirement, went back to school, taught and did volunteer work. But the Dahmer case was never far away.

"It's the defining moment in his career and his life, in a sense," said Chris James Thompson, the local director of the independent documentary. "At the same time, it's this horribly dark moment for the city."

Dahmer was convicted in 1992 of killing and dismembering 17 people (consuming some of them) and sentenced to 957 years in prison — where he was later killed.

When Kennedy first saw Dahmer, the suspect was hogtied and bleeding on the ground, Kennedy recalled in an interview related to the documentary. "He had been in a hell of a fight with two big police officers," Kennedy said in the interview. "He was whining, almost like a little baby."

Early in questioning, Kennedy recalled, "He cried, he ranted and raved, he got up and moved around kind of in a rage." Kennedy decided to "treat him as almost fragile."

After about three hours, Dahmer began to talk. "He said to me, 'But Pat, when I tell you what I'm going to tell you, you probably will hate me,' " Kennedy said in the interview with TheLip.tv.

Over his weeks with Dahmer, Kennedy came to view him with compassion.

"He was a pathetic soul," he said.