Leonir Gart, 39, president of Russia's Luge Federation and allegedly a close friend of President Vladimir Putin, was found dead in the sea in the Brac Channel on Sunday.
Split County Police spokeswoman Marina Kraljevic Gudelj told Hina on Tuesday police were establishing whether he drowned, had a heart attack or if there was foul play.
County Prosecutor Rene Laura said her office had ordered an autopsy and that the results would be known in a couple of days, adding that only then would it be known if the death was suspicious.
Asked if it was true that a Russian investigator had arrived in Split to help in shedding light on the case, Laura said the County Prosecutor's Office knew nothing about it.