OKLAHOMA CITY - News Channel Four has obtained the taped confession of Clayton Lockett recorded 15 years ago. It came with prison files that detailed his stay behind prison walls.
In it, he talks in detail about the night he shot Stephanie Neiman and watched his two accomplices bury her alive.
"I could hear her breathing and crying and everything," said Lockett while casually smoking a cigarette.
Just two days earlier, Lockett, his best friend, Shawn Mathis and cousin, Alfonzo Lockett, broke into a man's home to rob him. That man was Bobby Bornt.
"I had the shotgun in my hand and I popped him in the head with the barrel, and he looked and seen the shotgun and calmed down and he said don't kill me, don't kill my son," said Lockett.
The men began ransacking Bornt's home.
Then, Neiman pulled into the driveway to drop off her friend.
"I said, 'Let's take them out in the country and leave them.' and they said, 'No. We can't do that. We'll still get caught.' and I said, 'The only thing we can do is take them to the country, and kill them.'," confessed Lockett.
Bornt and the other woman, whose name we are protecting, promised not to tell on the three criminals.
Lockett claims Neiman refused to keep quiet.
"I couldn't convince her not to tell," said Lockett.
He shot her twice with a sawed off shotgun, and watched the other men bury her.
Photos inside his prison file show that grave circled in red.
Also in the file, a glimpse of his time on death row. He was caught with prison shanks and fought up until the day of his execution.
At that time, guards ended up tazing him because he refused to leave his cell.
Lockett's confession was more than 30 minutes long.
Throughout it, he never seemed to show any remorse when talking about his victims.
In the prison records, there is a letter that Lockett wrote in which he threatens one of his victims and says, "Cause I'm an assassin-- point blank!"
Watch Clayton Lockett’s full confession below.
WARNING: Graphic language and gruesome details may be upsetting to some.