Film-maker Louis Theroux has spoken of his uncomfortable interviews with the victims of Jimmy Savile after failing to expose the entertainer as a sexual predator during the making of a documentary 16 years ago.
Theroux spent three months with the man who would be revealed as a prolific sex offender years later, and famously quizzed him on-camera about allegations of abuse.
He went on to maintain a friendship with Savile, even staying on occasion at the former Jim'll Fix It presenter's house.
In a new film to be aired on Sunday, Theroux will revisit the subject to try to "understand the truth more fully" by talking to Savile's victims, friends and family, including those he was introduced to by the DJ.
Theroux said that he only noticed a clip of Savile embracing two women in an "overly physical way" in 2001 when he looked back at the raw footage during the making of the new programme.
His first programme was made before allegations over Savile's sexual offences had been made public, and Theroux said that in hindsight it was "tempting to see clues everywhere".
He recalls a "random comment" on a tape in which Savile "referred to his bed as an altar, because that's where the 'sacrifices' happen".
"Or in the overly physical way he embraced two women at Leeds' Flying Pizza restaurant one evening, which I only noticed looking back at the rushes," he adds in the BBC Magazine article.
Included in Sunday's programme will be interviews with four of Savile's victims, which Theroux admitted were "slightly uncomfortable" given his history with the entertainer.
He feared the victims would see him "as yet another person who failed them, by not doing more to expose Jimmy Savile while he was alive".
The film-maker said one of the victims felt Theroux had been "hoodwinked" by Savile when they saw the initial documentary.
Theroux wrote: "It was oddly bracing to feel the force of their unvarnished feedback. 'I remember thinking: poor Louis', said one. Another remarked on how 'silly' I seemed, being pushed around by a puffed-up celebrity."
Sunday's programme will also explore the impact Savile's crimes had on his victims and how he escaped justice for so long.
In October 2012, a year after his death at the age of 84, an ITV documentary called The Other Side of Jimmy Savile broke the story of the sexual abuse scandal.
The full extent of Savile's crimes was revealed in Operation Yewtree's report in 2013, which recorded 214 criminal offences committed by the star.
A further Department of Health report found he committed sexual assaults at 28 NHS hospitals.