Twenty people have now come forward to claim they were victims of sexual abuse by Sir Cyril Smith.
At least one victim has told detectives he was raped by the 29-stone politician, whose alleged child sex abuse activities at Knowl View School, a children's home in Rochdale, spanned nearly three decades.
Smith is alleged to have preyed on youngsters both at Knowl View, where five complainants have come forward, and another school in Rochdale for difficult children, Cambridge House, where 10 complainants have spoken to police.
Another five say they were abused at various other locations, all in the Greater Manchester area.
Police are now discussing with lawyers the charges Smith would have faced if he was still alive, to give "closure and clarity" to victims.
All the offences are said to have happened between 1960 and 1987.
Smith, who died in 2010, was the subject of allegations and investigations over decades during his career, first as a prominent local councillor in Rochdale and later as the town's Liberal MP. He was never prosecuted.
Detective Chief Superintendent Russ Jackson, of Greater Manchester Police (GMP), said today: "We are committed to understanding the enormity of Cyril Smith's misconduct and working to try to understand that, and thereby, provide a picture of the extent of his offending, and with the CPS (Crown Prosecution Service) to get to a position of what we would have done had he still been alive, and thereby provide that understanding to the victims who have gone through such a horrid time."
Three separate files regarding Smith's activities were passed to the director of public prosecutions and the Crown Prosecution Service, although on each occasion no prosecution was pursued.
Mr Jackson said in total 24 people have made complaints against 37 suspects involved with Knowl View, which is now closed down.
Rochdale Labour MP Simon Danczuk claimed in a recently published book that Smith raped a number of young boys at the residential school.
Police, spies and politicians helped to hide the historical child abuse carried out by Smith, according to Mr Danczuk's book, Smile For The Camera: The Double Life Of Cyril Smith.
It left Smith free to abuse children as young as eight despite 144 complaints by victims, Mr Danczuk and co-author Matthew Baker said.
A separate investigation, Operation Clifton, has been launched by GMP to find out if corruption by police, Rochdale councillors or council officers played a part in any alleged cover-up at Knowl View.
Such is the scale of child sexual abuse now being uncovered, around 50 detectives, about a quarter of GMP's major incident team, are working on historical sex abuse cases.
These include investigations into children's homes Broome House in Didsbury and Rose Hill in Northenden, both Manchester, where 13 people have made complaints of sexual abuse.
One victim says he was raped by three members of staff at Broome House. Eleven suspects have been identified in that inquiry.
Another inquiry is also investigating Wood End Assessment Centre in Atherton, near Wigan, involving 30 complainants spanning alleged offences dating from the 1960s.
Home Secretary Theresa May announced in July a new review into the handling of historic allegations of child abuse allegedly involving a cover-up by Westminster politicians.
Separate from sexual abuse in local authority institutions, GMP are also conducting Operation Doublet to tackle street grooming arising out of earlier investigations into sex abuse by Asian men in Rochdale.
So far more than 100 men have been either spoken to or will be by police. No charges have yet been brought.