The exact cause of 'Jackass' star Ryan Dunn's death is unknown because of the violent nature of his car crash on Monday morning (20.06.11).
The autopsy result for the actor and Zachary Hartwell - who was also killed when Ryan's Porsche flew over a barrier and into a tree on Route 332 yesterday (20.06.11) - were both dead when officers arrived on the scene, and according to TMZ.com the Chester County Coroner has confirmed it is impossible to determine how they died.
Toxicology results will determine the role alcohol played in the accident but will not be revealed for at least four weeks, but he did post pictures hours before the accident of him enjoying himself in a bar.
He said: "We are devastated by the tragic loss of Ryan Dunn - a beloved member of the MTV family for more than a decade.
"The 'Jackass' brotherhood will never be the same."