Three disturbing Cluedo cards from Lord Lucan's board game were discovered in the aristocrat's abandoned car, according to reports.
Richard John Bingham disappeared on November 8, 1974 after his children's nanny was found murdered.
Sandra Rivett was discovered bludgeoned to death by a lead pipe in his Belgravia home before the earl vanished.
He has not been seen since and was declared legally dead in October 1999.
Ten years ago, it was claimed Lucan had fled to Africa after the murder. In 2020, it was suggested the fugitive is still alive and living in Australia.
Now the Daily Mail reports the chilling find may offer new clues about the mystery.
Three cards representing Colonel Mustard, lead piping and the hall all came from his set of the board game and were reportedly discovered by detectives in his Ford Corsair at the time.
The find has never been made public before.
A former investigator told the publication: "If Lucan did leave the Cluedo cards, it makes me think the whole thing (the murder) was pre-planned.
"It is interesting. It is strange. The more you think about it, the more it has got implications."
The Mail also claim that during the 2004 review into the case, police became aware of another alleged sighting.
They interviewed a woman who claimed that she met Lord Lucan at a party in Portugal weeks after Ms Rivett's murder.
Monday marks the 48th anniversary of her death.
There are a huge number of theories on what became of Lord Lucan and long list of “sightings” – from backpacking on a volcano to living as a hippy in India.
Some believe he boarded a ferry at Newhaven, others think he got on a private jet at Headcorn in Kent to fly across the Channel where he was picked up by a limo.
And one source insisted he had committed suicide and his body was then fed to tigers at the Kent zoo owned by his pal John Aspinall.
Det Chief Supt Roy Ranson, who led the original murder investigation, claimed in his book that he believed Lucan fled to Africa with the help of influential friends. He was convinced that the discovery of Lucan’s car in Newhaven was a red herring.
He also believed Lucan flew to Portugal in a private plane belonging to former Formula One champion Graham Hill, who died in 1975. Later “evidence” suggested that Lucan was in Mozambique in 1975.
The first reported sighting of Lucan was in January 1975 when he was supposedly spotted in Melbourne, Australia.
Five months later he was “seen” in France at Cherbourg and St Malo. Police in South Africa examined fingerprints, supposedly left on a beer glass by Lucan in Cape Town.
Sightings were reported in southern Africa, first in Mozambique and then Zimbabwe, and there were even claims he lived in India as a hippy called “Jungle Barry”.
If still alive, Lord Lucan would be 87.
