Kirk Jared Rivers, now 22, walked in and handed officers a note, confessing to the killing of John Pogacar, who was 39 when he was brutally stabbed several times inside his Rancho Cordova, CA home.
He added that his father found his body.
Sacramento County Sheriff's spokesman John Ramos said: "He handed one of our officers a note, basically claiming responsibility for a homicide that happened four years ago."
He added that detectives were skeptical to begin with but he revealed details that only the killer could had have known, they knew they had their man.
They are still baffled as to why he chose this moment to turn himself in, but like Pogacar's friend Jesse Jurado, they are delighted he turned himself in.
Jurado told Fox 40: "We are so happy. We've been praying to God that this is what we've been waiting for. His family needs closure."
He added of his friend: "He was a very large man. He's a big teddy bear, a great guy to be around. He was a beautiful man. We are happy his killer has been caught."