The father of tragic 16-year-old Becky Watts wants his daughter's murderer to face the death penalty and said he would carry out the execution personally.
Grieving Darren Galsworthy said killer Nathan Matthews had evaded justice after brutally murdering his own stepsister.
Matthews murdered Becky after hatching a sexually-motivated plot to kidnap her with his girlfriend Shauna Hoare, 21.
Asked on BBC2's Newsnight if he wanted Matthews dead, Mr Galsworthy said: "Of course. Without a doubt.
"That might shock a few people, especially people who know me because I ain't like that.
"But the thing is, I was asked the question, do you think you've got justice? Well, no, I don't.
"They're still quite happy breathing and getting three meals a day. Apparently she's having horse riding lessons."
"If they were going to hang him, I would pull the lever, so no one else would have to carry that guilt."
The killers, who shared an interest in petite teenage girls, let themselves into 5ft 1in Becky's home in Crown Hill, Bristol, on February 19 last year.
She suffered more than 40 injuries before being suffocated by Matthews, then was bundled into the couple's car.
Her body was dismembered in their home in Cotton Mill Lane, Bristol, and was discovered by police in a nearby garden shed.
In November, former TA soldier Matthews was convicted of Becky's murder and jailed for a minimum of 33 years.
Hoare was jailed for 17 years after being found guilty of Becky's manslaughter. Both were convicted of conspiring to kidnap her.
Mr Galsworthy, who has a "recurring dream" that he is witnessing the murder, said he is still waiting for answers from Matthews. The killer always maintained his stepsister's death was a kidnap-gone-wrong.
Mr Galsworthy said: "I want the truth, that's all we ever wanted.
"Not this useless stack of lies that he's tried to come up with."