Here's the details:
Footage of the attack shows Irwin swimming above a 2.5m stingray before it turns on him and sends a poisonous barb through his heart.
Producer, director and life-long friend John Stainton yesterday said Irwin did not provoke the stingray and was simply swimming above it when he was attacked.
"He came over the top of a stingray and the stingray barb went up and into his chest and into his heart," Stainton said.
"It's likely that he possibly died instantly when the barb hit him, and I hope he felt no pain."
One of Irwin's contemporaries, internationally known cameraman and spearfisherman Ben Cropp, was in his own boat off Port Douglas when Irwin was killed.
"I have just spoken to a cameraman friend who was there and has seen the footage," Mr Cropp told The Australian last night.
"He was up in the shallow water, probably 1.5m to 2m deep, following a bull ray which was about a metre across the body - probably weighing about 100kg, and it had quite a large spine.
"The cameraman was filming in the water."
Mr Cropp said the stingray was spooked and went into defensive mood.
"It probably felt threatened because Steve was alongside and there was the cameraman ahead, and it felt there was danger and it baulked.
"It stopped and went into a defensive mode and swung its tail with the spike.
"Steve unfortunately was in a bad position and copped it.
"I have had that happen to me, and I can visualise it - when a ray goes into defensive, you get out of the way.
"Steve was so close he could not get away, so if you can imagine it - being right beside the ray and it swinging its spine upwards from underneath Steve - and it hit him.