Simoncelli was involved in a fatal accident during the 2011 Malaysian GP at the Sepang International Circuit.
"Marco lost his helmet in the crash. The officials said that, when the track medics got to him, he was in cardiac arrest. They tried to resuscitate him in the ambulance and the medical centre" say Matt Roberts as a BBC MotoGP presenter.
The Malaysian Grand Prix has ended in tragedy after Marco Simoncelli was killed in a horrific accident on the second lap of the race. The San Carlo Gresini rider lost the front end of his Honda going through turn 11 on the second lap.
The death was the first fatality in MotoGP since Daijiro Katoh, also a Gresini rider, passed away as a result of injuries sustained in the 2003 Japanese Grand Prix. The last fatal accident in the world championship series came when Moto2 rider Showa Tomizawa was killed at Misano last September.
Video Marco Simoncelli Crashed in Sepang - Malaysia
RIP for Marco Simoncelli.