Fayetteville, N.C. — A man suspected of killing his brother and sister-in-law more than 25 years ago in Cumberland County pleaded guilty Monday to two counts of first-degree murder, the Cumberland County Sheriff's Office said. 

A judge sentenced Sean Patrick McDuffy, 51, to 20 years in prison for each count of first-degree murder in the deaths of Kelly McDuffy, 24, and Bobbie Michelle McDuffy, 20, who were found dead Feb. 21, 1985, in their home at 437 Squirrel St. in the Bonnie Doone community. 

Both had suffered sharp force trauma to their upper bodies, authorities said. News accounts at the time reported a butcher knife was found in Kelly McDuffy's side. 

Sean McDuffy, who lived with his brother and sister-in-law at the time of their deaths, was the prime suspect early on. A judge ruled there was no probable cause for his arrest in 1986, however, and he was released.

The case remained closed until Bobbie McDuffy's dying father asked investigators to reopen it.

Starting in September 2007, detectives sifted through boxes of evidence, investigative notes and crime scene photos and again narrowed their focus to Sean McDuffy.

Sean McDuffy returned to North Carolina in 2009 after serving 13 years in jail in Georgia for trying to decapitate his girlfriend in an argument. Georgia Department of Correction records show that he was given a 15-year sentence in 1996 for charges that also included cruelty to children.