"I'm about to be executed for a crime I did not commit," Leavitt told KBOI-TV senior reporter Scott Logan from Death Row in a phone interview Friday afternoon.
Leavitt, 53, is scheduled to die by lethal injection Tuesday for what a judge called "a grossly inhumane act of murder that went beyond all decency."
The incident occurred on July 18, 1984 in Blackfoot.
On that day, prosecutors say Leavitt repeatedly stabbed 31-year-old Danette Elg in the bedroom of her home, using exceptional force, and then cut out her sexual organs either as she died or shortly afterward.
Leavitt knew Elg, who two days before her murder called police about a prowler at her home. She identified Leavitt as the prowler.
Following Elg's death, but before her body was found, Leavitt contacted police and expressed concern that she was missing.
On July 21, 1984, with Leavitt present, Blackfoot police entered Elg's home and discovered her mutilated body.
Police also found Leavitt's blood at the murder scene. He gave different stories about how his blood got there, but ultimately said he had a nosebleed while visiting Elg earlier and wiped his nose with her clothing. | What's it like on Idaho's Death Row?
But Leavitt continues to maintain his innocence.
"I did not kill, I was not there, I did not mutilate," Leavitt told KBOI-TV.
The convicted killer says he has passed two lie detector tests.
While those results may not be admissible as evidence, Leavitt says it's all he can do to show he's innocent. He says he is resigned to his fate if he dies next week.
"I'm prepared for Tuesday," he said. "I've made my peace with God - I know where I'm going."
Leavitt said he plans to use his remaining days visiting with family and talking with his attorneys.
"I hope the people of Idaho, who I am dying in the name of, can sleep a lot better at night..." he said.
The 54-year-old said he has no plans to issue any final words on Tuesday, where he's scheduled to die at 10 a.m.
"If I do get executed maybe the citizens of Idaho will wake up a little bit and take a look and say, 'shouldn't this person at least have been given clemency...," he said. "There's nothing else I can do to show you, or to prove to you that I didn't do it but say, 'I didn't do it.'"
Leavitt will be offered baked chicken, fries and milk for his final meal.