Peter Pickering, 80, dubbed the Beast of Wombwell, has been locked up in psychiatric hospitals since 1972, when he admitted the manslaughter of schoolgirl Shirley Boldy, in the Barnsley area of South Yorkshire.
Leeds Crown Court has heard how Shirley was 14 when she was abducted, raped and killed by Pickering.
A woman now in her 60s has told a jury how she was violently raped by Pickering just a few weeks before this killing.
Giving evidence last week, she described how she was picked up by the defendant, who later took her to a secluded spot where Pickering cut off her underwear with a knife, raped her, burned her breasts with cigarettes and told her she was going to be killed.
The woman told the jury: "I remain of the fervent belief that whether he has a mental illness or not the man is a monster and wherever he is now that's the right place for him to be."
Summing up the case for the prosecution, Michelle Colborne QC, reminded the jury that the woman has "never told a soul" about what happened to her until the police rang her in 2016.
She said she had not even told her husband.
Miss Colborne said: "What possible gain could there be for her? Why would she put herself through this?"
Sasha Wass, defending, told the jury that she did not doubt that what happened to her in that van "must have been terrifying" and that "she must have thought she was going to be killed".
Ms Wass said the question was her client's mental state at the time of the incident and whether he believed the woman had consented as it was happening.
She said Pickering was "mentally too unwell to grasp the situation and may well have believed that she was consenting".
Ms Wass referred to the complainant as a "remarkable woman" and agreed her client had "gone berserk" in the van.
Pickering, who appeared in court via video link from Swindon Crown Court, in Wiltshire, denies rape and false imprisonment.
He declined to give evidence in his defence during the trial.
The jury has been told that he was subjected to a hospital order without limit of time in 1972 for the manslaughter of Shirley Boldy by reason of diminished responsibility.
He has never been released and is currently being held at Thornford Park Hospital, in Berkshire.
On Monday, he sat listening to the barristers' speeches and the judge, wearing a blue raincoat and leaning on a walking stick.