New DNA. New reward money. New looks at cell phone data. New hope that a mysterious Putnam County double murder might soon be solved.

This week marks 10 years since Shirley Dermond (87) was bludgeoned to death, Russell Dermond (88) was beheaded, and a killer vanished.

FBI Atlanta Special Agent Andy Smith has been investigating the Dermonds’ murders for nine years, and admits it’s been incredibly frustrating.

“The evidence, and the way these crimes were committed, in over 20 years at the FBI, I’ve never seen a case like this,” Smith tells WSB.

In May 2014, friends became concerned when the beloved couple did not show up as promised to a Kentucky Derby party one evening.

Finally, when an alarmed friend went to the couple’s home, Russell Dermond’s decapitated body was found in his garage, with towels spread nearby. His wife Shirley was missing, leading to fears of a kidnapping, but days later, fishermen found her body in Lake Oconee. An autopsy showed she’d died of blunt force trauma before her body was weighted down with concrete blocks. Gunshot residue on Mr. Dermond’s clothing hinted that he had likely been shot, and his head removed to stymie ballistics matching, theorized Putnam County Sheriff Howard Sills.

The FBI is offering a $20,000 reward to unearth new clues in the case.

“We hope that that generates leads, provides new information. Look, we’re not just focusing on the DNA evidence, we’re not just focusing on the cellular data. We’re looking for any information from any location that we can get,” says Smith.

Smith says over the past decade, they’ve used a lot of techniques to identify suspects, analyze cell phone tower data, and examine DNA samples at multiple labs across the United States. Smith says Putnam County Sheriff Howard Sills believes they now have some of the best evidence to date to generate leads.

New technology which was unavailable in 2014 is being used on raw cellular data, which the FBI is helping analyze.

A laboratory in Utah confirmed a mixture of DNA found with Russell Dermond’s body--his, and someone else’s.

“This is the first time that we have confirmation of a sample that did not belong to Russell or Shirley Dermond,” says Smith. “That DNA that’s being tested now was located at the crime scene of Russell Dermond.”

Smith says despite the DNA discovery, there may be challenges.

“We want enough of a sample to not only use CODIS (the Combined DNA Index System), [but] to also do genealogy testing,” explains Smith. “So the sample has to be of a high enough quality and a big enough sample for us to do both.”

“Any other leads you might have that you could mention?” WSB’s Veronica Waters asked.

Smith paused for several long seconds.

“No,” he said.

“You’re thinking, ‘What can I say, what can’t I?’ Is that what I’m seeing? You’ve got to keep some things close to the vest?”

“Yes,” Smith said. “We do.”

Smith says the murders have affected a wonderful middle Georgia community, the sheriff, and the sheriff’s investigators. He says there’s worry about the health of Sheriff Sills and his investigators, who spend countless hours, even nights and weekends, working to solve it.

“It never goes away,” says Smith. “It’s hard on that community to know that something like that can happen in that community.”

With the $5,000 reward offered from the Putnam County Sheriff’s Office, the total is now up to $25,000.

“This case has taken several investigators’ lives to a hard level,” Special Agent Smith says, but adds these latest steps in the probe are far from last-ditch efforts.

“We will never stop. We never stop,” says Smith. “We will solve this case.”