French tennis star Mathieu Montcourt, 24, suffered cardiac arrest when he died Monday, an autopsy has revealed.
Montcourt, ranked No. 119 in the world and who reached the second round of the French Open in June, collapsed and died Monday night. His girlfriend raised the alarm when she found him in the hallway of his apartment building, lying in front of his door.
French police say the toxicology tests conducted on Montcourt's remains were negative, and that the athlete died of natural causes.
The player's body will be buried Friday. His family and teammates will hold a memorial service at the Rolland Garros stadium in his honor, shortly afterward.
Montcourt was entering a bumpy stretch in his career as his five-week ban from competition kicked off Monday. He was found to have gambled on other players' games over the Internet last summer.
Originally banned from the circuit for eight weeks, the Court of Arbitration for Sport reduced his suspension to five weeks after determining that Montcourt had not bet on his own matches.
The French team's technical director called Montcourt a promising athlete, in full growth.
"He was a hardworking player, serious and healthy," Patrice Dominguez wrote in a statement. "He was also a very kind boy, open and very curious."
Dominguez was interviewed by French police Tuesday, after it emerged Montcourt had spent his last evening at his house in the company of his son.
Montcourt's teammates were shocked by the news of his death.
"We shared a dorm room for two years," the world's No. 8-ranked player, Jo-Wilfried Tsonga, told newspaper L'Equipe. "Since this morning, tears come to my eyes each time I think of him."
"It's violent," added Richard Gasquet, "I've known Mathieu since I was 9."
Tennis champion Rafael Nadal was among the first to express his condolences after Moncourt's death.
"This morning, I woke up with one of the worst news anyone can receive," Nadal wrote on his Web site Tuesday. "I am still under shock for this. I can't believe it."
Montcourt and Nadal, also 24, knew each other since competing at the international junior level, and later as professional tennis players.