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NEW YORK -- A man who was convicted of killing a debt-ridden motivational speaker by stabbing him in a staged street crime was sentenced to prison Monday in a case that tested the limits of assisted suicide.

Kenneth Minor yelled an expletive after he received a 20-years-to-life sentence for Jeffrey Locker's July 2009 death.

"Only two people in the world know what happened that night, and one of them is not here no more," said Minor, whose voice sometimes broke as he addressed the court.

"I was going to pay for the part I played in this situation. And I would be the first to stand up as a man to take responsibility.... I'm no animal, and I ain't got no malice in my heart," Minor said.

"In the end, a life is a life. And I ask your forgiveness," he concluded.

The case was unusual for broaching the concept of assisted suicide in the context of strangers staging a seeming street crime.

Locker approached Minor on an East Harlem street to ask for help with a death he wanted look like a robbery, so his family could collect as much as $18 million in life insurance, both prosecutors and Minor said.

Locker, 52, who co-authored a 1998 self-help book and gave presentations on handling workplace stress. But he was deep in financial trouble himself, partly because of his investment in a $300 million Ponzi scheme run by Backstreet Boys and `N Sync mastermind Lou Pearlman.

Minor was a down-and-out stranger, a former computer technician with a record of drug arrests. He said he initially balked at Locker's request but started to feel sorry for him after hearing about his money troubles.

Prosecutors said Minor went beyond aiding suicide by stabbing the 52-year-old Locker seven times in the self-help expert's car.

"This was murder for money, not a mercy killing," Manhattan District Attorney Cyrus R. Vance Jr. said after Minor's conviction last month.

Minor said he only held a knife while Locker repeatedly lunged into it.

"He was taken advantage of. ... He's no contract killer," his lawyer, Daniel J. Gotlin, said in his closing argument. He has said Minor plans to appeal.

Locker's family has been unable to collect most of the insurance money. His widow, Lois, said in a statement last month after the verdict that it would "be good to put this part of the healing process behind us."

Criminal cases surrounding assisted suicide have often concerned terminally ill people and the medical providers or relatives who help them end their lives. But a few other cases besides Minor's have involved looser relationships and people who weren't sick.