Jockey Stathi Katsidis, the 31-year-old brother of boxer Michael Katsidis, was found dead in his home outside Brisbane, Australia, according to The Sydney Morning Herald.

He apparently was found by his partner, Melissa Jackson, in Hendra, a suburb of Brisbane, the newspaper reported. No cause of death was reported, although another publication reported that there appeared to be no suspicious circumstances.

Katsidis, a successful jockey, reportedly had a history of drug-related problems. He tested positive for ecstasy in 2008, the newspaper reported, for which he served a nine-month suspension. And the same year he was caught driving drunk, for which he was fined $1,000 and suspended for another six months.

He also had problems making weight, for which he reportedly blamed some of his behavior.

Michael Katsidis, who lives in Las Vegas, is scheduled to fight Juan Manuel Marquez on Nov. 27 at the MGM Grand.