Jackass star Ryan Dunn was driving at 130mph in his Porsche when he fatally crashed, said police, in what one officer described as the worst accident he had ever seen.

Ryan Dunn’s Jackass co-star Bam Margera has visited the site of the car crash where he broke down in tears, saying, “I can’t get through this.”

Dunn crashed his car after leaving Barnaby's, a pub in West Chester, Pennsylvania.

Jackass star Ryan Dunn
Jackass star Ryan Dunn

He had tweeted a photo of himself and Zachery Hartwell – who was also killed in the crash – drinking with a third man drinking just hours before the crash.

However the manager of Barnaby's, Jim O'Brien, told the Philadelphia Inquirer that although Dunn was drinking with several friends at the bar but didn't appear drunk.

Officials say the toxicology results for Dunn and, which would help determine the role alcohol played in the crash, will be released in four to six weeks.

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Autopsy results for both men, released by the Chester County Coroner, reveal that the crash was so violent that it is impossible to determine if Dunn and Hartwell died from the impact itself or from the resulting fire.

The cause of death for both men was stated as blunt force trauma and thermal trauma.

On Tuesday, Bam Margera appeared distraught on U.S. TV as he visited the site where his best friend and co-star Dunn had died.

Margera stood at the guardrail that Dunn’s car smashed through with such force that the Porsche travelled through about 40 feet of trees before exploding into flames.

“He was the happiest person ever. The smartest guy, he had so much talent and he had so many things going for him. It's just not right,” Margera openly sobbed.

"I can't (get through this). Do you know how horrible it is being on an airplane for six hours, not being with everybody – just stuck.

"It was the worst phone call I've ever gotten in my life waking up to that."

Margera also revealed that he experienced an unexplained bout of anger at the exact moment when his friend was killed.

"I've never lost anybody that I care about. It's my best friend. I was in Arizona when I heard and I remember I was with some friends having the best time ever and at 12.30 I just started punching out the windows of the van and ripping out the speakers.

"I don't even know why, I wasn't mad at anybody or anything and if it's 12.30 there (in Arizona) then that means it's exactly when he crashed.”

Bam's mother April Margera has defended Dunn, saying she does not believ he would drink and drive.

“I have yelled at him for lots of things but he was not a big drinker and he was always responsible as far as I know, so I cannot believe he would do that,” April told NBC Today Show.

Here's what happened when Bam Margera visited the scene of Ryan Dunn's car crash.