MOSCOW — Family, friends, teammates and thousands of fans paid their last respects Wednesday to Alexei Cherepanov, the 19-year-old rising hockey star who died after suffering heart problems during a game outside Moscow.

The cause of his death was still under investigation, federal investigators said Wednesday. A first-round draft pick for the New York Rangers, Cherepanov collapsed on the bench during a game Monday outside Moscow.

State television showed mourners in his Siberian hometown lining up on a red carpet placed on the ice in the hockey stadium of Cherepanov's team, Avangard Omsk, to lay flowers at his coffin.

Crowds of mourners followed as pallbearers carried the coffin, draped with white cloth, from the stadium to Omsk's Staro-Severnoye Cemetery, where Cherepanov was buried.

Some onlookers were so overcome with grief they had to be restrained.

"It is hard to evaluate today the depth of the loss felt by the family of Alexei, Russian sport, and the Avangard team," said Leonid Polezhayev, the governor of the Omsk region, in comments to Russian agency Regnum.

"Alexei Cherepanov wasn't only a talented athlete and a reliable comrade, he was an idol of modern youth."

Moscow regional investigators said Cherepanov apparently had chronic ischemia — a medical condition that means not enough blood gets to the heart or other organs. They have raised questions as to why the condition went undetected.

Federal investigators released a statement Wednesday saying they had ordered tests of blood and other samples to see if there was any evidence of doping. They also had questioned the manager and medical staff of Avangard as well as staff at the Vityaz stadium, where Monday's game was played, the statement said.

Meanwhile, lawmaker Pavel Krasheninnikov, who sits on the Russian Hockey Federation's supervisory council, has accused emergency workers of taking too long to respond to the call. He also complained there was no ambulance on standby for the game and no defibrillator.