'Jackass' star Ryan Dunn, 34, and passenger Zachary Hartwell, 30, both of West Chester, Pennsylvania, died of blunt and thermal trauma due to car accident in the pre-dawn hours on Monday, according to city officials.

The accident involving Dunn's Porsche 911 took place at approximately 2:38 a.m. on Route 322 in the area of Pottsdown Pike, according to David J. Garver, Chief Deputy Coroner for the Chester County Coroner's Office.

The car was fully engulfed in flames in the woods when police arrived, according to West Goshen police.

Speed may have been a contributing factor to the accident, police said.

Both occupants were pronounced deceased at the scene by the Chester County Coroner's Office.

Toxicology tests on their bodies are being conducted and will be released by the West Goshen Township Police Department upon receipt of the written report of the findings.