Jackass Star Ryan Dunn's Autopsy Under Way as Passenger in Fatal Crash Is ID'd

Stuntman's cause of death is forthcoming as authorities reveal that MTV crew's longtime P.A. Zachary Hartwell was riding with Dunn at time of fatal crash

Speculation may be raging on, but the world is getting closer to some definitive answers in the death of Ryan Dunn.

The investigation into the fiery crash that killed the Jackass stuntman is continuing apace as the 34-year-old's body has been autopsied to determine a cause of death and provide an answer to the question of whether alcohol played a part in the fatal crash. So far, authorities have simply said that speed may have been a factor.

Meanwhile, another question was answered today: that of the identity of Dunn's passenger.

Authorities have ID'd the passenger in the 2007 Porsche as West Chester, Pa., resident Zachary Hartwell, 30.

How is Hartwell related to the Jackass crew?

Hartwell, an Iraq war vet, was friendly with Johnny Knoxville and Bam Margera and the rest of the stunt boys and worked as a production assistant on Jackass Number Two. He lived near Dunn and Margera and was among the pals with Dunn at the Barnaby's of America bar in Pennsylvania in the hours before the accident. (Dunn tweeted a photo of the outing prior to departing with his friend, though it has since been removed from the social networking site.)

The car crash that ended Dunn's life happened sometime around 2:30 a.m. Sunday. The car hit a siderail and tree before bursting into flames.