Police in Australia have released previously unseen photographs from their investigation into the murder of British backpacker Peter Falconio 25 years ago.

Falconio, from Huddersfield, was shot on a remote stretch of highway near the Northern Territory town of Barrow Creek, about 186 miles (300km) north of Alice Springs on 14 July 2001.

His body has never been found and police hope the images could jog memories that could lead to a tip-off. His killer, Bradley Murdoch, died of throat cancer aged 67 in jail last year, without disclosing where Falconio’s remains might be.

The images include a full length picture of Murdoch staring straight at a camera during the police investigation.

Falconio’s girlfriend Joanne Lees escaped from Murdoch, hiding in scrubland for several hours before she was able to wave down two men driving a truck.

One of the photographs taken by police shows Lees looking traumatised in the hours after the attack. Others show injuries she sustained, including after her wrists were bound with cable ties.

Northern Territory Police Force Commissioner Martin Dole said that 25 years was a “significant milestone” and that he hoped the release of new images could jog memories or lead to a tip-off.

“This was a traumatic and horrific event for Ms Lees, and for Peter’s family, who have now gone such a long time without the answers they deserve,” Dole said.

“While a murderer has been held accountable for his crimes, this investigation can never be considered closed until Peter’s remains are found and his family can lay him to rest.”

Other photos released by NT Police include of the orange Volkswagen Kombi van the couple had been driving as they travelled around Australia. It was found abandoned just off the Stuart Highway close to where the attack took place. Pictures of the crime scene are also among the tranche of pictures.

During his trial in December 2005, the court heard Murdoch, who was then 43, pulled up beside their vehicle, claiming to have seen sparks coming from the camper van Falconio was driving.

He then shot Falconio in the head as he inspected the vehicle, before taking 28-year-old Lees into his car and binding her wrists with cable ties, although she managed to escape.

Murdoch was convicted of Falconio’s killing by a unanimous jury verdict, and he was also found guilty of the assault and attempted kidnap of Lees.

He had always maintained his innocence, despite DNA evidence linking him to the crime, and unsuccessfully appealed to overturn his convictions twice.

A few days ago police released bodycam footage of an interview with Murdoch a week before his death, as they tried to get him to reveal the location of the body.

In a statement on Tuesday, Commissioner Dole said: “It is deeply regrettable that Murdoch died without, as far as we know, ever disclosing the location of Peter’s remains. His cowardly silence has denied his family, friends and loved ones the closure they deserve.”

NT Police remained “committed to bringing this investigation to its fullest conclusion” and would “continue to pursue every avenue available,” he added.

A reward of up to A$500,000 is on offer for information leading to the discovery of Mr Falconio’s remains.