CHARDON, Ohio -- A serial killer already serving multiple life prison terms has pleaded guilty to a fifth slaying and has been sentenced to death.

Edward Edwards, who's 77, pleaded guilty Tuesday in Ohio's Geauga County to killing his 25-year-old foster son in 1996 for $250,000 in life insurance.

A three-judge panel sentenced him. He had asked for the death penalty. But the victim's sister, Jai-Dean Copley of Garden City, S.C., told The Plain Dealer newspaper of Cleveland that life in prison would be harsher.

Edwards already has been sentenced to life prison for killing a young couple in Ohio in 1977 and another couple in Wisconsin in 1980.

His 1972 autobiography details how he drifted across the country in the 1950s and 1960s, running scams, robbing gas stations and seducing women.