Tommy Hope, 48, was found dead of multiple stab wounds in his Camdenton home on April 28, 2004. An initial investigation with more than 60 leads yielded no arrests.
Camdenton Police Chief Laura Wright said authorities believe the murder was drug-related.
On Monday, Clara Rector of Laurie, who was incarcerated on unrelated Camden County stalking charges, was questioned. Clara, who was a person of interest in 2004, admitted to stabbing Hope. At the time of the original investigation, there was not enough evidence to directly connect her to the murder.
Camden County Sheriff Dwight Franklin said the confession came while questioning Rector about Rector's alleged stalking of a Camdenton pastor.
"We talked to the individual and subsequently got a confession. It was information pertaining to the homicide...detailed information...only a person that was there would be able to give us that information," Sheriff Franklin said.
Court documents say Rector "left her house in the middle of the night on April 24, 2004, and went to Mr. Hope's residence to obtain and use drugs."
The probably cause statement goes on to say that Rector grew angry when Hope did not have any drugs for her, and she said "I was high and not thinking...I jumped on his back and cut his throat."
Clara was charged with first-degree murder and felony armed criminal action. The 36-year-old had bond denied.
On Tuesday, Clara's husband, Jason Rector, was arrested for evidence tampering by the Morgan County Sheriff's Office and Camden County SWAT officers at his Laurie home. He was not a suspect during the original investigation.
Jason was charged with felony tampering of physical evidence. The 46-year-old also had bond denied.
Both subjects are being held in the Camden County Adult Detention Facility.
When notified of the arrests, Hope's sister said they were the answers to her prayers, according to Wright.