10/12/2012 04:12 GMT

Lord Lucan: Mysterious 'Boyfriend' At House Where Nanny Sandra Rivett Murdered

A mysterious "boyfriend" could have been living with Lord Lucan at the time the family nanny was murdered, and the 7th Earl of Lucan vanished, a new statement has revealed.

BBC Inside Out reported that Lady Sarah Gibbs, sister of Lord Lucan, told police at the time of the disappearance that another man was sleeping at the house. He may have been having a relationship with one of a number of women in the household.

Nanny Sandra Rivett was killed in 1974, and an inquest ruled that she was murdered by Lucan, who had vanished and has never been seen since.

Lord Lucan and Lady Lucan, before the murder

Lady Sarah, who died in 2001, told police in a statement that her four-year-old niece Lady Camilla Bingham told of a mystery man who sometimes slept in "nanny's room" and sometimes slept in "mummy's - because she's got a gigantic bed.

"We were talking about home, that is 46 Lower Belgrave Street and Camilla said the boyfriend always stays upstairs while we have lunch until we ring the buzzer.

"I said 'Where does he live?'. She said 'He lives in the house with us'."

Although the statement appears to imply the man was the boyfriend of Lady Lucan, estranged from Lord Lucan, Lady Sarah is believed to have said she thought the man was Sandra Rivett's boyfriend, according to the Sunday Mirror.

Lord Lucan was declared officially dead by the High Court in 1999.

The Lord said in a letter unearthed after his disappearance that before the murder he had witnessed an unknown man fighting with his estranged wife, Lady Lucan.

Lord Lucan's brother Hugh Bingham has called for the evidence the BBC uncovered to be investigated.

"I'm encouraged by the idea that there is a fresh source of evidence and that I feel wants to be given a fair hearing and this seems to me to be one way of achieving that," he told the broadcaster.

Sandra Rivett, who was allegedly murdered by Lord Lucan

"Let us hope that now with the way in which the evidence seems to be gathering, there is a chance that maybe the inquest result could be set aside.

"If that happened then the warrant of arrest would fall away and my brother's situation would be restored to the normal situation of a man innocent until proven guilty."

Retired Det Sgt Graham Forsyth, who witnessed Lady Sarah's statement, told Inside Out he believed Rivett may have had a boyfriend who stayed over at the house.

Since Lord Lucan's there have been more than 70 alleged sightings of him from Colombia, to Goa to Gabon.

Lady Lucan has publically stated since the late 1980s that she does not believe her husband to be still alive.