Detectives from Operation Midland want abuse victims and potential witnesses to come forward to assist them in their probe into the suspected gang.
They are appealing for any information from people who lived in or visited Dolphin Square in central London in the 1970s.
The residential development near Parliament has long been popular with MPs.
Officers believe the abuse took place at locations in London and the Home Counties, including military bases, between the mid-1970s and mid-1980s.
An alleged victim – known as Nick – has come forward, claiming he was abused from the age of seven to 16 at a number of locations including a flat in Dolphin Square.
Nick has alleged he was abused by single men, groups of men and at “parties”, and that other young boys were present who were also abused, police said.
Detective Superintendent Kenny McDonald, the lead officer for the operation, 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.”
He said people who lived in or visited Dolphin Square in the 1970s “will have seen or heard something that they only understand the significance of now”.
Operation Midland is one of 18 strands of investigation that come under Operation Fairbank and there have been 1,000 witnesses and 900 documents so far.