Jacksonville, Fla. – A jury found James Leon Jackson guilty of first-degree murder and sexual battery in the death of 10-year-old Tammy Welch, a case that has gone on for over 30 years.

READ MORE: Testimony has started for man accused in 30-year cold case

The verdict comes a day after jurors heard from Jackson, 66, after he was accused of killing Welch back in 1984.

The morning of Welch’s murder, Jackson told investigators he went over to his estranged wife’s apartment complex to take a nap after she went off to work and his children left for the first day of school.

“I went over there to take a nap on the couch and a few hours later, my friend started knocking on my door and asked to come in because there had been a body discovered outside,” Jackson said. “When homicide detectives came to interview me, I asked them what does her murder have to do with me?”

Prosecutors questioned why Jackson didn’t have a different demeanor with investigators.

“Police find a body just a few feet away from where you were sleeping and your first response was, 'What does that have to do with me?' they said.

Earlier that morning, prosecutors presented DNA evidence from Jackson that matched fluids recovered from clothing at the crime scene. Jackson said he willingly gave investigators a sample of his sperm because he didn’t commit the crime.

“I never met Tammy, I didn’t even know she existed,” Jackson said.

Defense attorneys argued that the DNA evidence presented could not guarantee a perfect match to Jackson and that further forensic damage could be tainted as well.