We should warn you, it is disturbing to hear Jon Dunkle explain what he did and why. But there is another intriguing story here -- two brave women played important roles in getting him to confess.
On the tape recording Joe Farmer can be heard saying, "On the screen is Jon Scott Dunkle with Rich Fogarty, Belmont police."
By the time he stepped in front of the camera, Dunkle was 25 years old and ready to put on a show.
"When I was in 6th grade, I had an urge to kill," said Dunkle on the tape as he took Belmont police on a tour of his crime scenes.
Dunkle: And I killed him and placed his body up on top of the mountain.
Farmer: Did you want to take us up there or just walk right on up the trail?
Farmer: OK, go ahead.
He showed them where he stashed one of his murder weapons, seemed to get emotional a couple of times, and became annoyed by detective Fogarty's questions.
Fogarty: What was going through your mind at the time?
Dunkle: Let's go through everything and then have questions.
"I started in Belmont in 1971 and we never had a case that was even close to this magnitude. It really had the community locking their doors wondering what's going on," said former Belmont Police Investigator Rich Fogarty.
John Davies, 15, disappeared from his Belmont home in the middle of the night. Lance Turner, 12, died near his daytime soccer practice. Sean Dannehl, 12, died in a Sacramento park just after dark. And police suspected Dunkle in each of the crimes -- they even told the media -- but they lacked evidence to make an arrest. Their last resort paid off.
"When he moved to Sacramento, we planted a female detective in the fast food restaurant he was working in," said Fogarty.
Undercover Officer Lisa Thomas became Dunkle's drinking buddy, wore a wire, and called for backup when he snuck into a Sacramento area home. While Dunkle awaited trial on the burglary charge, his first victim's mother volunteered to try and get him to confess to the murders.
"We had to get closure, it was tearing... I mean, it was ruining our family," said Joan Davies, John's mother.
Joan knew Dunkle well since he was a family friend who hung out with her boys. She drove to the state prison at Jamestown. By this point, her son -- also named John -- had been missing for almost four years.
"I knew the minute I walked in and I looked at him that he had murdered John. After they left me alone with him, he started to tear up when I kept saying over and over again, 'Jon, we need to know,'" said Joan.
Dunkle did not crack at Jamestown, but those familiar with the case tell me Joan set the stage. When Dunkle began serving his burglary sentence at the men's colony in San Luis Obispo, he started a sexual relationship with his cellmate, Charles Rice, and told him about killing the boys. Rice turned Dunkle into authorities, hoping to get a deal on his own manslaughter charges.
Rice: You say there's wolves on top of here?
Dunkle: Yes, there is.
Rice: We should probably keep ready.
Detectives thought Dunkle would be more talkative with his cellmate there. The two joked about Dunkle returning to the scene of the Davies murder in the months after and finding wild animals.
Dunkle laughs at Rice: Don't get paranoid.
Rice: What do you mean don't get paranoid? You're talking about wolves. Don't get paranoid, hmm.
Dunkle told detectives he went to the Davies house after 2 in the morning, convinced the boy to drink beer with him at Edgewood Park, and then stabbed him in the back with a paring knife.
Dunkle: And he said get the... get a stick out of his back which I had already pulled it out, I believe.
Dunkle said he also stabbed Davies in the throat, but dropped the knife, so he finished him off with a 12-inch round rock.
Dunkle: Uh, what ya?
Rice: Huntin' for bones. I don't see no bones.
His cellmate couldn't find any remains, but the map Dunkle drew lead a search team straight to the spot along Highway 280.
Farmer: This is the first bone that was found and the time is approximately 1:20. OK, the shoe will be item number 6.
And the undercover officer was there helping wrap up the case.
Farrmer: Lisa Thomas again pointing to the skull.
Lance Turner's body was found in the woods near Ralston Middle School in Belmont, just hours after his soccer practice there.
Farmer: Mark, move a little bit to your right. I'm going to zoom in on the feet, OK?
Students spotted someone who looked very much like Dunkle at the scene around the time of the killing and even helped an artist draw an accurate sketch, but Dunkle ran free for two and a half years before he finally confessed.
Dunkle: And I saw Lance run down, he had a gold cross country shirt on.
Dunkle also gave a detailed description of killing Sean Dannehl saying he knocked him off his bike in a Sacramento area park and stabbed him to death.
Dunkle: When I first saw Sean Dannehl, I knew I was going to kill him.
Dunkle blamed marijuana and alcohol for fueling his desire to kill, and he explained why he decided to finally confess.
Dunkle: I need help and as the judge sees this movie, he'll know it anyway. So whatever. (laughs) That's it.
We obtained a current picture of Dunkle from San Quentin at age 52. The death sentence he received for the murders is currently on hold because a federal judge decided he's incompetent to help in his own appeal.
I received a bizarre letter from Dunkle that you can read here. You can also see last week's investigation, where I explore Dunkle's possible connection to the disappearance of Kevin Collins back in 1984.