Seven alleged victims of Jimmy Savile made complaints to four separate police forces while the disgraced television presenter was alive.
The claims were made to police in Surrey, London, Sussex and Jersey but it was decided that no further action should be taken.
Scotland Yard said on Thursday that a retired officer had told them he had investigated Savile in the 1980s while based in west London but did not have the evidence to proceed.
Commander Peter Spindler said he believed the allegation was of an indecent assault, possibly in a caravan on BBC premises in west London, but officers have still not found the original file.
Another allegation, of inappropriate touching dating back to the 1970s, was made by a woman in 2003, but this was treated as "intelligence" by police because the victim did not want to take action.
Surrey Police submitted a file to the Crown Prosecution Service containing references to four potential offences, including an allegation of indecent assault on a young girl at a children's home. The allegations related to three potential victims in Surrey and another in Sussex, and Savile was interviewed under caution in 2009, but prosecutors decided there was insufficient evidence to bring charges.
The seventh allegation emerged in 2008 when Jersey police received a claim that an indecent assault occurred at children's home Haut de la Garenne in the 1970s. Again it was decided that there was insufficient evidence to proceed.
Claims have been made that former DJ Savile, who died last year aged 84, targeted children while they were in hospital. He had a bedroom at Stoke Mandeville Hospital, an office and living quarters at Broadmoor and widespread access to Leeds General Infirmary.
Officers have also searched a cottage belonging to Savile in Scotland to look for "any evidence of any others being involved in any offending with him". Savile is said to have entertained a number of celebrities at the cottage in Allt na Reigh in Glencoe.
A Lothian and Borders Police spokesman also said the force has received two complaints about Savile's behaviour - one in Edinburgh and the other in Newcastle.
