Someone had set his clothing alight and tried to make an improvised firebomb by heating up containers of household chemicals in a microwave oven.
It was likely that Mr Ross was already dead from stab wounds and blunt force injuries to his head and neck, the High Court at Livingston was told.
David Nairne, 26, a prisoner at Edinburgh, is on trial for allegedly murdering Mr Ross in February this year. He denies the charge.
He also pleads not guilty to attempting to defeat the ends of justice by setting fire to the dead man’s clothing, trying to make the fire spread faster and disposing of evidence, including the murder weapon.
He further denies headbutting Mr Ross in Mathers Bar in Edinburgh nine months earlier in June 2010.
At the start of the trial, which is expected to last for five days, the Crown refused to accept a plea of guilty to a reduced charge of culpable homicide.
David Hepburn, 49, watch commander with Lothian and Borders Fire Service, said he arrived at the scene in Pilton Drive North a few minutes after a neighbour dialled 999 at 2.30am on Sunday February 27..
A team wearing breathing apparatus who extinguished the fire in the bedroom found Mr Ross lying face down on the floor.
Mr Hepburn said the body was badly charred and the double bed extensively damage.
He said: “The body showed signs of wicking because the fats inside had started to render soaking the clothing.
“The body becomes in effect like a large candle. This phenomenon has been attributed to the old stories of spontaneous human combustion.”
He said there was extensive damage to the deceased’s legs, thighs and groin area.
“The clothing seemed to be burned off,” he said.
The trial continues.