The couple lived in Sydney together before touring the country

Senior constable Ian Spilsbury said swabs taken to test Mr Falconio's van for gunpowder were still in storage.

The admission came at a committal hearing at Darwin Magistrates' Court.

Bradley Murdoch, 45, denies shooting the 28-year-old from Yorkshire and abducting his girlfriend Joanne Lees, 30, in the outback three years ago.

His defence counsel Mark Twiggs asked Constable Spilsbury why swabs looking for gunpowder residue on Mr Falconio's Kombi van had not been processed in the laboratory.

Relationship

The officer, who examined the crime scene, said his superior had asked him to delay the tests until he received further information.

Mr Twiggs also asked why a stick of lip balm was not found at the crime scene for three months.

Ms Lees, from Huddersfield, said she used it as a lubricant to free herself from handcuffs made by her alleged attacker.

Police arrested Bradley Murdoch in November

Ms Lees gave a description to police of a dog belonging to her alleged attacker, but the defence team have suggested she changed her story.

Earlier, the court studied a police video and photographs of the crime scene.

On Thursday, Ms Lees admitted having a sexual relationship with another man in Sydney before she and her boyfriend visited the outback.

Body missing

Mr Murdoch is accused of killing Mr Falconio and abducting and assaulting Ms Lees near Barrow Creek, north of Alice Springs, in July 2001.

She claims he flagged down the van before shooting her boyfriend and abducting her, although she managed to escape.

Mr Falconio's body has never been found.

Mr Murdoch denies the charge and the committal hearing will determine if he will face a full trial.