THE parents of backpacker Peter Falconio cried in court today as they heard a barrister deny allegations that their son staged his own disappearance.

Joan and Luciano Falconio, from Hepworth, wept in the public gallery at the back of the Northern Territory Supreme Court in Darwin as Rex Wild QC insisted one day their son's body would be found.

Bradley Murdoch, 47, of Broome, Western Australia, denies murdering Mr Falconio. He has also denied abducting and assaulting Mr Falconio's girlfriend, Joanne Lees, after flagging down the couple's camper van on a remote stretch of highway near Barrow Creek, about 200 miles north of Alice Springs, on July 14, 2001.

Referring to suggestions made by the defence that Mr Falconio, who was 28, could have staged his own disappearance, Mr Wild said: "He's not disappeared himself, as in my learned friend's description, he has been disappeared by Bradley Murdoch."

Mr Wild told the jurors he had heard the case described as the "Falconio mystery".

"In our submission, there's no mystery. Peter Falconio died on July 14, 2001."

He said it was not surprising the body had never been found.

"You live in the Northern Territory. You know how remote central Australia is. It's not difficult to hide a body. One day it will be found."

Mr Wild added Mr Falconio had "everything to live for". He was with a loving partner, on the trip of a lifetime, and had watched a beautiful sunset at Ti Tree at about 6.30pm and "shared a smoke" with her. Both had birthdays coming up in September, and were planning to celebrate in Fiji with friends.

He said Miss Lees had gone through a terrifying experience.

"What we've got to remember is the agony of the moment - her focus is on the man, her focus is on where she finds herself, her focus is on escaping," he said. "This young woman is in a state of emergency. She is, in fact, fighting for her life."

Mr Wild said claims of corruption by police officers were nothing more than offensive innuendo.

"Corruption, conspiracy, this innuendo running through the case, there's not one bit of evidence to support it," he said. "Every time it's been put in this case, it's been denied."

If officers had wanted to "fit up" Murdoch then they could have made the evidence against him even stronger, giving the example that Miss Lees's DNA could have been planted on hair ties found on Murdoch and his DNA could have been "poured all over" the evidence, but it had not been.

"Here, what you have in this case, is the evidence as it is," he said. "It's not evidence that's been doctored or messed about with."

He told the jury that handcuffs used to tie Miss Lees had been meticulously put together.

"Miss Lees was handcuffed, thrown out of the vehicle, hit the ground, and punched and manhandled before she escaped. We can only guess what would have happened if she had not escaped."

He said the attacker then covered the pool of Mr Falconio's blood on the highway with dirt and moved the body.

"You might think the man that put the dirt on the blood and moved the body is a meticulous and fastidious man, which Mr Murdoch is."

Mr Wild described Murdoch as a "big, strong man" with strong opinions. He said he was an experienced truck driver who took amphetamines to stay alert while transporting large quantities of cannabis from Sedan in South Australia to Broome in Western Australia.

He added that Murdoch carried guns with him on his journey, "for his business".

Mr Wild also told the court Murdoch cared more for his dog, Jack, than he did for other people.

"He has been very dismissive of other human beings."

He said Murdoch had also shown "strange behaviour" in the witness box, pointing to the instance when he accused Mr Wild of using tricks and labelled him "disgusting" when the prosecutor offered him a magnifying glass to view an exhibit during cross-examination.

"It was a peculiar response and gives you some idea of the way Mr Murdoch reacts under what he perceives as some pressure."

Later, Mr Wild said: "The defence called three eminently qualified expert witnesses.

"They added precisely zilch to the defence case, they took nothing away from the prosecution case."

Earlier, Grant Algie, defending Murdoch, highlighted how the evidence of some prosecution witnesses had changed over the last four years.

He said Miss Lees had told police she was forced from the front of her attacker's vehicle into its rear through the front seats, but had told the court she was now not sure about this.

He also said Miss Lees told police her attacker's vehicle had a chrome or silver bull bar and a beige or khaki canopy. Murdoch's vehicle had a black bull bar and a green canopy, with no front-to-rear access.

Mr Algie said: "Is it good enough, when you are told to deliberate on a man for murder, to accept the shifting sands of the description of the man's vehicle? Four years down the track, when my client's on trial for murder, we hear: `I'm not sure.'

"Well that's OK, we can still try Bradley Murdoch for murder even though his canopy's different."

He referred the jury to images drawn by art teacher David Stagg, in consultation with Miss Lees.

"These images and the descriptions from Joanne Lees on which they are based are likely to be the very best and most reliable evidence you have got of the vehicle driven by this man at Barrow Creek.

"And every time one of these descriptions or images does not match Bradley Murdoch, that's cogent and important evidence that you are entitled to use."

Closing his arguments, Mr Algie said: "Guilty, members of the jury, is a verdict that carries with it a degree of absolute certainty.

"It says Bradley Murdoch is a murderer. He killed Peter Falconio and you are satisfied of that beyond a reasonable doubt.

"But a verdict of `not guilty' does not have the opposite effect. It does not have the same degree of certainty.

"A verdict of not guilty does not mean Peter Falconio is alive, or that Joanne Lees is a liar, or that nothing happened at Barrow Creek.

"It can simply mean that while something happened at Barrow Creek, you're not sure what it was."

The trial was adjourned until tomorrow, when Mr Wild will continue his closing arguments.