ATLANTA, Georgia (CNN) -- Gary Michael Hilton pleaded guilty Thursday to killing hiker Meredith Emerson, and was sentenced to life in prison.

Gary Michael Hilton was escorted into court Thursday under heavy security.

Hilton, 61, wore an orange jumpsuit and bulletproof vest as he sat somberly through the sentencing.

He was charged with kidnapping with intent to harm and malice murder in Emerson's January 4 death.

The 24-year-old University of Georgia graduate disappeared on New Year's Day while on a hike in the North Georgia mountains with her dog.

Emerson's parents gave emotional statements in court.

"I feel that no punishment for Mr. Hilton is too great," said her father, David Emerson. "I only pray that he suffers immensely for his heinous acts."

Susan Emerson, the victim's mother, said she was not sorry that prosecutors took the death penalty off the table.

"I feel like he should stay alive and slowly rot," she said. "As far as I am concerned, there is no such thing as justice in this case. Nothing will bring our daughter back." Watch the Emersons describe their feelings about Hilton »

Dr. Kris Sperry, the state's chief medical examiner, concluded Emerson died of blunt force trauma to the head and was decapitated after death.

Witnesses said they saw Emerson on Georgia's Blood Mountain with Hilton.

Days later, Hilton led authorities to her body, reportedly in a deal to avoid the death penalty.

"Anyone's emotional reaction would have appropriately be that this defendant deserved the penalty of death," said Lee Darragh, Hall County District Attorney at a news conference following Hilton's plea.

But after much deliberation, research and consultation with other prosecutors, Darragh decided a life sentence "in practical terms" is a "death penalty in and of itself."

"The most appropriate course was to have this defendant take responsibility for the death of Meredith Emerson through his guilty plea today," he explained.

Hilton would not be eligible for parole until he is 91 years old. "He will most likely die in prison and most certainly never see the light of day again," said Darragh.

Emerson's family agrees with the sentence, a family spokeswoman said.

"Today is the last day of a very long month, but January on its last day is a safer place than January on its first," Peggy Bailey told reporters. "There are sources of joy that will lead our families through the suffering and on to healing."

Investigators also suspect Hilton in the October slaying of Irene Bryant and the presumed death of her husband, John, in Transylvania County, North Carolina, said Sheriff David Mahoney. Authorities haven't specified what evidence they have.

Hilton also is the suspect in the death of Cheryl Dunlap, 46, whose body was found in December in Apalachicola National Forest, southwest of Tallahassee, Florida, according to authorities. E-mail to a friend

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