A NEW investigation into the horrific Moors Murders is televised tomorrow.

Programme makers claim that new material about killers Ian Brady and Myra Hindley, including letters and photographs, could help solve one remaining mystery - the whereabouts of victim Keith Bennett's grave.

But senior police officers have rejected claims that photos kept by Myra Hindley could provide vital clues to where one of her victims is buried on the Saddleworth Moors, straddling the A635 Greenfield Road above Holmfirth.

The BBC2 documentary claims the pictures, originally seized after the pair's arrest in 1965, could identify 12-year-old Keith's grave.

He went missing 40 years ago as he walked to his grandmother's Manchester home. His body has never been found.

But Greater Manchester Police said the photos do not identify any location.

The documentary, The Moors Murder Code, claims police reopened their investigation after they were handed letters Hindley wrote to her mother Nellie from jail.

They showed the importance she and Brady attached to the photos - originally seized by police after their arrest.

Police stored copies of them before returning the originals to the convicted killers.

The author of the documentary, Duncan Staff, says after Hindley's death he was handed 200 pictures that were in her possession as well as her unpublished autobiography.

In it, Hindley reveals that she and Brady were using pictures to record the sites of their victims' graves.

But a spokeswoman for Greater Manchester Police said: "We would like to be clear that the material featured in the documentary did not prompt police to reopen the investigation into Keith Bennett's murder."

She said police had looked at the photographs but found they were too vague to identify any specific location.

According to newspaper reports, one image showing Myra Hindley clutching her collie dog bears a resemblance to a photo used as a `marker' for the grave of another victim, 12-year-old John Kilbride.

But the police spokeswoman said: "The work that has been done on the photograph has proved to be fruitless."

At their trial in 1966, Brady and Hindley were convicted of the murders of Lesley Ann Downey, 10, and Edward Evans, 17. Brady was also found guilty of murdering John Kilbride, 12.

Although they were suspected of killing 16-year-old Pauline Reade and Keith Bennett, there was no evidence.

But in the 1980s, Greater Manchester Police began a new investigation on the bleak moors above Meltham and Holmfirth.

Interviewed behind bars, Brady and Hindley finally admitted to the crimes. They were taken separately to Saddleworth Moor to try to find the bodies.

Eventually, the police managed to locate the remains of Pauline Reade, but despite many weeks of digging, they were unable to find the body of Keith Bennett.

The documentary also reveals that after discussions with chiefs at GCHQ spy centre in Cheltenham, detectives last year employed code-breakers to uncover hidden messages Brady and Hindley sent each other in poems and letters.

But these gave no clues about the location of Bennett's body.