Ipswich sex worker killer Steve Wright has been urged to "stand up" and admit carrying out the infamous murder spree by his elderly father.
The forklift truck driver was handed a full-life jail term for the murder of five young women who vanished in 2006 but has never acknowledged his guilt.
Locals suffered six weeks of terror while detectives hunted for the serial killer, his victim's naked bodies appearing in isolated locations around the Suffolk town.
In the wake of his conviction there were calls for Wright to face the death penalty from some of the women's families.
Ten years on from the disappearance of his first victim, Conrad Wright, 80, called on his son, now 58, to confess.
He told BBC Suffolk: "It's the only thing he can do, I mean he's a man ... but he doesn't do it does he?
"It's the only thing he could do to excuse himself is to stand up and admit it.
"I wouldn't forgive him, you can't forgive him - their lives were taken away, you don't forgive anybody for that anyway."
On October 30 2006 Tania Nicol, 19, vanished from Ipswich's red light area, followed by Gemma Adams, 25 around two weeks later, triggering a major inquiry.
Miss Adams' body was found in a stream at Hintlesham on December 2, followed by the discovery of Miss Nichol's corpse in a pond at Copdock on December 8.
Two days later the body of Anneli Alderton, 24, was found in woods at Nacton and sex workers in the town were urged to stay off the streets.
On December 12 the bodies of Paula Clennell, 24, and Annette Nicholls, 29, were found near woods at Levington.
Wright was arrested at his Ipswich home a week later.
His father told the BBC: "The Steve I know ... he'd go to cricket at the weekend, and he'd come with me and look after the other two dogs we had then, he'd go down the road to the pub ... he wouldn't say boo to a goose."
Mr Wright said he did not know where his son was imprisoned, but would ask to hear the truth if they met again.
"And knowing him, he'd probably say, 'well, I don't know,' he would, and that would be his answer.
"And I'd say well you've murdered people and he'd sit back and say: 'Have I? I can't remember.'"
During a trial at Ipswich Crown Court Wright admitted having sex with the women but denied murdering them.
Following his conviction in February 2002 he was given a full-life term - sentences only handed out in the gravest cases - to join the ranks of Jeremy Bamber, Levi Bellfield and Rose West.
Relatives of Miss Nicol said at the time: "These crimes deserve the ultimate punishment and that can only mean one thing."