Swindon taxi driver Christopher Halliwell has been urged by his daughter to give the family of a second woman he killed "justice" over her murder.
Natasha Halliwell said her father, who is beginning a life sentence for the murder of nightclubber Sian O'Callaghan, should "do the right thing" and "tell the truth" over the murder of missing prostitute Rebecca Godden.
"He needs to give the other family closure as well and give them the justice they need for their daughter," she told ITV Daybreak.
The 20-year-old was speaking after her father, of Asbury Avenue, was jailed for life after pleading guilty at Bristol Crown Court to Miss O'Callaghan's murder.
But he escaped justice over the murder of Miss Godden because of a police blunder.
Halliwell, 48, admitted to a senior detective that he murdered Miss O'Callaghan and Miss Godden, and even led officers to their bodies.
A High Court judge ruled that the confessions the father-of-three made during a three-hour period on the day of his arrest were inadmissible because Detective Superintendent Steve Fulcher breached police guidelines governing the interviewing of suspects.
The detective, who was leading the hunt for Miss O'Callaghan, failed to caution Halliwell and denied him a solicitor.
The ruling by Mrs Justice Cox meant that Wiltshire Police had no other evidence against Halliwell to link him to Miss Godden's murder and the charge was withdrawn.
Miss Godden's father has hit out at police, saying they had "made massive mistakes".