A former drifter serving a life sentence for one slaying and sentenced to death for another has been indicted in the murders of an elderly couple in a third state.

For years, authorities have called Gary Michael Hilton, 65, a suspect in the killings of John and Irene Bryant, who disappeared in 2007 while hiking in Pisgah National Forest in North Carolina.

It wasn't until late last month that a federal grand jury in Chattanooga, Tenn., indicted the alleged serial killer in the couple's murder.

Hilton, who was also indicted for kidnapping and robbing the couple, is serving a life sentence for the January 2008 slaying of Meredith Hope Emerson in the Dawson Forest Wildlife Management Area.

Dawson County Sheriff's Lt. Col. John Cagle was the lead investigator on the Emerson case before he retired from the Georgia Bureau of Investigation.

Cagle said last week he believed the evidence investigators in Georgia were able to recover during the Emerson case "will greatly enhance North Carolina's ability to convict Hilton in the deaths of John and Irene Bryant."

Earlier this year, Cagle was in a Florida court as Hilton was convicted and sentenced to death for the 2007 murder of a Cheryl Dunlap.

"I plan to go to North Carolina, just like I did for the Florida trial," Cage said.

Authorities have also named Hilton the prime suspect in the slaying of 27-year-old Michael Scot Louis, whose body was found at a Florida state park about the same time.

Hilton, however, has not been charged in that case.