Northern Territory police are investigating new claims about the whereabouts of murdered British backpacker Peter Falconio’s body.

The Northern Territory News has received a letter from an Australian ex-pat now living in London, and police have confirmed they are looking into it.

Mr Falconio was murdered on a remote outback road in one of Australia’s most notorious crimes.

The letter details how Mr Falconio’s body was cut up, put into plastic bags and taken to Adelaide and then to Perth by train before the remains were buried around Geraldton in WA.

However, the former lead investigator in the Falconio case has questioned the credibility of the anonymous letter.

“I guess the unique part about this is that I understand it does name an associate and gives police a line of inquiry,” Colleen Gwynne, who headed the investigation of the 2001 crime, told ABC radio.

“The account seems pretty bizarre and not very particularly logical that you would take a body across a couple of jurisdictions on a lengthy train ride in a couple of bags — it doesn’t make a lot of sense to me.”

Ms Gwynne said moving the body so far was risky and questioned why the letter writer would go to the media and not the police.

The letter writer says Bradley Murdoch, who was convicted of Mr Falconio’s murder, called an associate and told him to meet him in the outback because he needed help to dispose of a body.

“When they met, Murdoch told (the associate) that he had murdered a guy in self-defence. At the time, (the associate) had no idea who the victim was,” the letter to the NT News said.

“Murdoch had cut the body up and put it in two large … bags that were watertight and smell proof.”

The letter said Murdoch ordered the associate to drive to Adelaide and fly to Perth, but he decided to take the train instead thinking the bags would attract less attention.

“(The associate) told me he went way past Geraldton and buried both the bags unopened in a nice spot and even made up a cross,” the letter said.

In a statement to the NT News, a police spokesman said they were reviewing the letter to determine whether it should be investigated further.

The NT News reported further that it understood police received many letters each year from people claiming to know the whereabouts of Mr Falconio’s remains, but the specifics of this latest letter had “piqued their interest”.

Murdoch was convicted in 2005 of murdering Mr Falconio, 28, and assaulting his girlfriend Joanne Lees on a remote stretch of highway near Barrow Creek, north of Alice Springs, on July 14, 2001.

Ms Lees hid in bushland for five hours while Murdoch hunted her with his dog, before she managed to flag down a truck driver.

Murdoch is believed to have hidden Mr Falconio’s body, which has never been found despite extensive searches.