The man accused of murdering Briton Peter Falconio in Australia has said he does not know how his DNA got on the clothing of Mr Falconio's girlfriend.
Ms Lees has told the court the couple were flagged down
Bradley Murdoch, 47, admitted running drugs and said he was hundreds of miles away at the time of the alleged attack.
He denies murder and abducting Mr Falconio's girlfriend, Joanne Lees, near Alice Springs on 14 July 2001.
Mr Murdoch also told the Darwin court it was not him or his vehicle caught on CCTV in Alice Springs that night.
He said he had been in Alice Springs that day but left at 1530 local time to run cannabis across central Australia.
Mr Murdoch said he was more than 370 miles (600km) away at around 2000 local time, when the alleged attack took place.
The defendant said he could not explain how his DNA profile was found in a spot of blood on a T-shirt worn by Ms Lees on the night of the alleged attack.
"I know I went through Alice Springs. I don't know whether I crossed their paths or not," he told the Northern Territory Supreme Court.
He admitted changing his appearance and that of his vehicle after the trip, but said regularly doing so was necessary for drug running.
The prosecution had claimed Mr Murdoch tried to disguise his pick-up truck after shooting 28-year-old Mr Falconio on the Stuart Highway, north of Alice Springs.
After taking the stand for the first time, Mr Murdoch said he and another man, James Hepi, regularly ran "large quantities" of cannabis across Australia, stashed in a spare fuel tank on the back of his truck.
The defendant said he had since had a disagreement with Mr Hepi, who has testified against him.
Mr Murdoch denied Mr Hepi's claims that he talked about ways of disposing of a body.
He did admit owning two guns which he carried for protection while transporting drugs.
Ms Lees, 32, of Brighton, told the court earlier in the trial she and Mr Falconio had been flagged down by Mr Murdoch while they were driving.
He is then alleged to have shot the backpacker and bundled his girlfriend into the back of his van, binding her in makeshift handcuffs.
Ms Lees said she later escaped and hid in the undergrowth for five hours until her abductor gave up searching for her and left.
The body of Mr Falconio, from Huddersfield, West Yorkshire, has never been found.
The trial continues.