Police investigating the disappearance of a former Brighton student believed to have been shot in Australia today confirmed blood found at the scene was his.

Peter Falconio, 28, has not been seen since he and his girlfriend Joanne Lees, 27, were held up by a gunman as they travelled in their camper van on a remote desert highway 175 miles north of Alice Springs.

Following DNA tests on Peter's father Luciano and brother Paul, 31, Northern Territory police said they believed blood found on the remote highway belonged to Peter.

Peter, a building surveyor and former student at the University of Brighton, left the city with Joanne, his girlfriend of five years who worked in Thomas Cook, last November to go on a round-the-world trip.

Police commander Max Pope said: "We now believe blood found at the scene is Peter's.

"The Falconio family have been told of this. Of course they didn't want to hear the news but I think they have accepted this."

Meanwhile, police said they were investigating the possibility that he was killed by someone stalking Joanne.

They were questioning friends of Joanne about the type of people the couple had met on their travels, looking into the possibility that she had been followed and then trapped by a stalker.

On Saturday night, moments after stopping on the Stuart Highway where they had been flagged down by the man, Joanne heard what she thought was a gun shot.

She was then tied up by the man and thrown into the back of a van but managed to escape into the bush where she spent several hours hiding from the gunman before raising the alarm.

But Peter, whose family live in West Yorkshire, vanished.

Peter's father and brother made an emotional visit to the spot where he disappeared yesterday.