A Glasgow teenager may still have been alive when he was set on fire after being stabbed, a court has heard.
Kriss Donald's body was found in the east end of Glasgow
A forensic expert told the High Court in Glasgow that Kriss Donald might have crawled down a grassy embankment before he died on a walkway above the Clyde.
Anne Ramage said her examination of the area suggested the 15-year-old tried to extinguish the flames by rolling in a muddy hollow.
Daanish Zahid, 20, denies assaulting, abducting and murdering Kriss in March.
He has lodged a special defence blaming three others for Kriss's abduction and death.
On Tuesday, the trial jury was shown extensive footage of the area taken at the time the teenager's burned body was found in the east end of Glasgow.
Ms Ramage, a forensic scientist with Strathclyde Police, said it was likely the fire was started at an area of newly-felled trees behind the nearby Celtic Supporters Club.
She claimed that Kriss then made his way down towards the Clyde before trying to extinguish the flames by rolling around in a muddy hollow near the cycle path where he was discovered.
Pc Graeme Rankin, 32, a specialist in surveying crash scenes, said he saw a number of pools of blood, patches of charred ground and grass and tyre tracks.
He said significant areas of blood had been found on a dirt track leading from behind the supporters' club and another between the logs, one of which had been particularly severely burnt.
Charred areas of ground were consistent with something moving over the area of its own accord as opposed to having been dragged, he said.
Pc Rankin said that suggested that Kriss had been attacked and was still alive when he was set alight.
He added that tyre marks at the scene matched a silver Mercedes which was found burnt-out on the night Kriss was allegedly abducted.
The trial, before Lord Philip, continues.