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Leandro Lo, one of the world's top jiu-jitsu fighters, was fatally shot inside a São Paulo nightclub early Sunday morning. He was 33. An off-duty police officer thought to allegedly be involved has turned himself in to authorities, according to The Washington Post.

"Lo was one of the greatest athletes our sport has ever produced," the International Brazilian Jiu-Jitsu Federation said in a statement. "Lo's global influence, passion and dedication to Jiu-Jitsu will forever be remembered and honored for the great champion and person he was."

Brazilian media has reported that there was an altercation at Clube Sírio, the club in São Paulo. A man allegedly approached Lo's entourage and attempted to get a rise out of the group. According to Lo's attorney Iva Sigueira Junior, the man picked up a bottle from their table and refused to put it back.

Sigueira Junior also stated that Lo knocked the man to the ground.

According to a witness who spoke to the Brazilian national television program "Fantástico," the man then "took four steps back," pulled out a gun from his waist and shot Lo at point-blank range.

Police issued an arrest warrant for military police officer Henrique Otávio Oliveira Velozo related to the fatal shooting and he turned himself in on Sunday afternoon.

Lo was one of the most decorates martial arts fighters over the past decade. He won five World Cup gold medals, eight World Championships andeight Pan American Championships during his career.

The star was slated to participate in another tournament in Austin, Texas later in August.