He said: "I appeal to men who were subjected to abuse 30 years ago to come forward.
"We are also investigating the murder of three young boys - we are determined to find answers."
Nick, not his real name, claimed he was one of between 15 and 20 children, who would be picked up in cars and taken to hotels and apartments, where they were physically and sexually abused.
Describing the members of the paedophile ring in an interview last month, he said: "They were very powerful people and they controlled my life for the next nine years.
"They created fear that penetrated every part of me, day in day out. You didn't question what they wanted, you did as they asked without question, and the punishments were very severe."
He added: "They had no hesitation in doing what they wanted to do. Some of them were quite open about who they were. They had no fear at all of being caught, it didn't cross their minds."
He said he had been present at a depraved sex party in the 1980s when a Tory MP had throttled a boy to death.
He said the murder took place at a luxury town house in London and was witnessed by a group of men.
Nick said he had been in the room, and described the victim as being aged around 12 and having brown hair.
He said: "I watched while that happened. I am not sure how I got out of that. Whether I will ever know why I survived, I am not sure."
On another occasion, Nick claimed a young boy, who was around 10, was deliberately run down and killed by a car being driven by one of his abusers.
A third boy was allegedly murdered during a depraved orgy at which another Tory MP was present, Nick has told detectives.
Detective Superintendent Kenny McDonald, who is the officer leading the investigation into the alleged murders, said he was convinced Nick was a credible witness.
He said: "Nick has been spoken to by experienced officers from the child abuse team and from the murder investigation team, and they and I believe what Nick is saying is credible and true, hence why we are investigating the allegations that he has made."
Detectives are now appealing for other victims or witnesses to come forward and speak to specially trained officers in confidence.