Stathi Katsidis' grieving fiancee Melissa Jackson has revealed how her act of kindness may have contributed to the champion Queensland jockey's death.Jackson is still in shock after finding Katsidis' body in their rented home at Hendra on Brisbane's northside early on Tuesday morning.Jackson regrets moving Katsidis, who she found asleep on their lounge around 3am (AEST), and placing a pillow under his head on the floor.An autopsy has failed to determine the exact cause of death but Jackson belie

Stathi Katsidis' grieving fiancee Melissa Jackson has revealed how her act of kindness may have contributed to the champion Queensland jockey's death.

Jackson is still in shock after finding Katsidis' body in their rented home at Hendra on Brisbane's northside early on Tuesday morning.

Jackson regrets moving Katsidis, who she found asleep on their lounge around 3am (AEST), and placing a pillow under his head on the floor.

An autopsy has failed to determine the exact cause of death but Jackson believes the 31-year-old suffocated.

"I know what the autopsy has said but I believe in my heart he suffocated," a weeping Jackson told AAP.

"He'd been drinking for 12 hours straight and couldn't walk but I couldn't carry him to bed.

"I was worried he might be sick in his sleep so I moved him to the floor and put a pillow under his head.

"He was fine then but when I woke later around eight he was in a similar position but face down in the pillow, dead."

Jackson's father, Tony Jackson, who is a police officer, said the autopsy report was inconclusive and the exact cause of death might not be known for several months.

"The autopsy report came back yesterday and was inconclusive," Tony Jackson said.

"Stathi's heart was fine and there was no trauma. We'll have to wait now for toxicology results which could take several months."

Melissa Jackson said the tragic day started with Katsidis playing tennis with fellow jockey Brad Stewart on Monday morning.

A drinking session at a local hotel followed with Stewart, his partner and two friends from Katsidis' home town of Toowoomba.

Jackson said they farewelled Stewart and his partner around 3pm (AEST) when they left the hotel to pick up her son from day care and returned home with his Toowoomba mates.

She said the group stayed at their home for a "boy's night in".

Jackson said she briefly quarrelled with Katsidis later that night about his partying and went to bed.

"I was just tired and didn't want to fight with him about his drinking," she said.

"I wasn't asleep and I could hear them mucking around so around 2am I went out and told his friends to leave."

Jackson said she went back to her bed but returned an hour later to check on Katsidis who was sleeping and snoring on their lounge room couch.

"Everyone was gone by then and Stathi was asleep on the couch," she said.

She then moved him to the floor with a pillow, fearing he might be sick.

Jackson said she normally never went to bed without Katsidis.

"I never go to bed without him but I gave up that night," she said.

"I should have brought him to bed with me somehow but I couldn't move him.

"I shouldn't have given him the pillow."

Katsidis' body has been released and a funeral will be held in Toowoomba on Tuesday.

Katsidis was to ride AJC Australian Derby winner Shoot Out in the $3 million Cox Plate at Moonee Valley on Saturday.

He had a history of drug-related problems and had a long battle with his weight.

He was disqualified for nine months but was allowed to return in seven months after testing positive to ecstasy in 2008.

In February 2008, Katsidis had a blood alcohol level more than three times the legal limit when pulled over by police at Toowoomba.

He was fined $1000 for drink driving and disqualified from driving for six months.