An Oregon man previously convicted of murder has been sentenced to life in prison after he was found guilty of a second homicide for the 1996 death of his wife, according to officials and reports. 

Brian Lee Clifton, 69, was sentenced to life behind bars on Thursday after pleading guilty to first-degree murder for killing is 43-year-old wife, Kathy Clifton, decades earlier, according to records and a report from the Law&Crime Network.

Clifton pleaded not guilty to the charge in September 2021 before reversing course Thursday, Oregon Judicial Department records show. 

OREGON POLICE OFFER $11,500 REWARD FOR INFORMATION ABOUT DEATH OF COLLARED FEMALE WOLF

Oregon’s Polk County Sheriff’s Office reported Kathy Clifton, née Thomas, was last heard from in March 1996, when she called Salem Police to report a hit-and-run crash. On Sept. 1, 1996, police learned of the discovery of human remains left "in the hills overlooking the Mill Creek area in rural Polk County."

According to police, the body was "wrapped up in a tarp and bound with rope."

Kathy Clifton smiling for a photo

Photo released by Oregon's Polk County Sheriff's Office shows Kathy Clifton. (Polk County Sheriff's Office)

"From doing sketches, CT scans, to 3D rendered images and even a real sculptures was made using the actual skull, to help put a face to the unidentified female," the sheriff’s office said in a September 2021 announcement. "Even with all the efforts made, the woman remained unidentified until 2019."

DEADLY OREGON AUTO ACCIDENT KILLS 1, DOZENS OF VEHICLE INVOLVED

Investigators used new DNA technology over the course of a 10-month period to identify the remains as belonging to Kathy Clifton.

black and white composite drawing of the human remains found in Sept. 1996.

Photo released by Oregon's Polk County Sheriff's Office shows a composite drawing of the human remains found in Sept. 1996. (Polk County Sheriff's Office)

But no one reported Kathy missing, police said. Instead, Brian Clifton moved out of the state and remarried in October 1996 — just one month after investigators discovered Kathy’s then-unidentified remains and despite the fact that he and Kathy were never divorced, police said.

Clifton was arrested on Aug. 13, 2021, when police said he confessed to "his involvement in the murder of Kathy."

PORTLAND COPS UNCOVER CACHE OF WEAPONS IN CONVICTED FELON'S TENT AS CRIME CONCERNS MOUNT IN CITY

"He told them how he had prepared to kill her. He had gotten a good knife, a good-sized knife, placed it in his bedside table," Polk County Deputy District Attorney Alicia Kay Eagan told an Oregon court Thursday, according to the Salem Reporter. "He lay beside her for several hours. She was asleep when he put the knife into the back of her neck the first time."

Brian Clifton in court

Photo released by Oregon's Polk County Sheriff's Office shows Brian Lee Clifton. (Polk County Sheriff's Office)

Polk County Circuit Judge Norman Hill was critical of Clifton for his apology, the Reporter stated. 

"You apologized for what happened," Hill said. "This wasn’t something that just happened. It wasn’t an accident. It was a deliberate, cold-blooded murder." 

CLICK HERE TO GET THE FOX NEWS APP

Prior to his marriage to Kathy, Brian Clifton was convicted for the strangulation murder of a motel worker in 1973, Law&Crime reported. He was sentenced to life in prison for that case, but was paroled less than 10 years later.