The wiry, graying drifter sought for several days in the New Year's Day disappearance of a 24-year-old hiker pleaded guilty Thursday to murdering her in what authorities called a frustrated robbery attempt.

In a startlingly swift resolution to the case, Gary Michael Hilton was immediately sentenced to life in prison with the possibility of parole after 30 years. The judge said she signed off on the deal because the 61-year-old likely would have died in prison anyway before the state had a chance to execute him.

Hilton was indicted Thursday morning by a specially called Dawson County grand jury that accused him of bludgeoning Meredith Emerson on Jan. 4, three days after he was seen with her on a trail in the mountains of northern Georgia.

Hilton told investigators he abducted the physically fit woman in a plan to steal cash from her bank accounts, Dawson County District Attorney Lee Darragh said.

"The sole purpose was to acquire (bank) cards and PIN numbers," Darragh said. "He mentioned at one point that he knew eventually he would take her life."

But Emerson gave him false PINs, and Hilton finally took a tire iron to her head, the prosecutor said. Hilton decapitated her to make it harder for authorities to identify the body, said John Cagle, a special agent in charge with the Georgia Bureau of Investigation.

Authorities have said they are looking at whether Hilton had a hand in the October disappearance of an 80-year-old hiker and his 84-year-old wife in western North Carolina, and in two other killings in Florida. Cagle and Darragh declined to say what effect, if any, Hilton's plea deal might have on those investigations.