A North Yorkshire Police officer is among five serving detectives served with misconduct notices over how they handled allegations relating to Jimmy Savile.
Two former officers are being investigated.
The Independent Police Complaints Commission watchdog said inquiries are being made into how officers working for Sussex, North Yorkshire, West Yorkshire and Surrey police forces dealt with claims about Savile’s predatory sexual behaviour.
Four serving detectives with Sussex Police are being investigated over their handling of a reported indecent assault carried out by Savile in 1970.
A detective sergeant and detective constable, who visited the complainant after she contacted the force in March 2008, have been served with gross misconduct notices.
The other two officers, a detective chief inspector and detective inspector, who had supervisory roles, have received misconduct notices.
Investigators have taken a statement from the woman and are due to quiz the four officers soon.
IPCC deputy chairwoman Sarah Green said: “The investigation is examining interactions between Sussex Police officers and the victim and whether all lines of inquiry were properly pursued.”
A serving detective sergeant with North Yorkshire Police has also been served with a misconduct notice over how he handled information from a 15-year-old girl regarding Savile and his late associate Peter Jaconelli in January 2002.
How two revelations made by a serving prisoner about Jaconelli in December 2008 and January 2009 were treated is also being investigated.
The investigation got under way following a referral from North Yorkshire Police in April over whether information it had on record about Savile and his associates was properly disclosed to Her Majesty’s Inspectorate of Constabulary (HMIC).
Meanwhile, a former inspector with West Yorkshire has been interviewed under criminal caution regarding allegations he “acted on behalf” of Savile by inappropriately contacting Surrey Police ahead of a police interview in 2009.
The IPCC said that its investigation into the matter is “nearing completion” and is also looking into what knowledge the former officer had of letters making accusations against Savile.
A retired detective inspector with Surrey Police is under investigation for his role in investigating allegations of sexual abuse by Savile at Duncroft School in 2007 and 2008 and whether information was passed on to other police forces in a “timely way”.
The watchdog said that no investigation into Metropolitan Police Service officers had been deemed necessary.
A spokesman said: “We have advised the MPS to ensure that if any further evidence comes to light they should consider a referral to the IPCC.”