By David Madden

PHILADELPHIA (CBS) — Officials at Graterford Prison have confirmed the death on an outlaw biker who admitted to the brutal murder of an Upper Darby police officer 13½ years ago.

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Thomas Campbell, who went by the street name “Tom Thumb,” had been on the lam from weapons charges when he came upon and murdered 10-year veteran officer Dennis McNamara.

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More than a year later, Campbell admitted his crime, in an effort to avoid the death penalty.

Campbell died of natural causes behind bars at age 65, according to a Graterford spokeswoman.

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Colleagues on the force remembered McNamara not just as a consummate professional but a genuinely decent guy, and suggest that Campbell’s passing might provide McNamara’s family and friends with a little closure.