-Bam Margera furious after American film critic tweets: 'Friends don't let jackasses drink and drive'
-Dunn posted Twitter picture of himself in a bar with passenger Zac Hartwell hours before crash
-Autopsy under way to determine if alcohol played a part
-Dunn was charged with drink-driving offence in 2005
-Star's burnt body 'had to be identified by his tattoos'
-Johnny Knoxville leads tributes saying: 'Today I lost my brother'
By Chris Johnson and Natalie Trombetta
Tragic: Jackass star Ryan Dunn was killed in a high-speed car crash yesterday. Film critic Roger Ebert tweeted a message insinuating that Dunn's accident was caused by drink-driving
Jackass star Bam Margera is outraged after film critic Roger Ebert tweeted a message blaming Ryan Dunn's fatal car crash on drink-driving.
Dunn, 34, died when his sports car flew off the road at around 2.30am on Monday while he was driving to his home in West Goshen, Pennsylvania, following a night out in a bar with friends.
Now his fellow Jackass co-star Margera, 31, has broken his silence after Ebert criticised Dunn hours after the smash.
Taking to Twitter soon after the news broke, Ebert, 69, who won a Pulitzer Prize for Criticism, tweeted: 'Friends don't let jackasses drink and drive.'
Wreckage: The blackened remains of the Porsche 911 GT3 are towed away fromt he crash scene in Pennsylvania.
A link to a news story about the accident accompanied his comment.
Margera retaliated on Twitter late last night, saying: 'I just lost my best friend, I have been crying hysterical for a full day and piece of s**t roger ebert has the gall to put in his 2 cents about a jackass drunk driving and [he is] one, f*** you!"
He added: 'Millions of people are crying right now, shut your fat f*****g mouth!'
Sources told TMZ that Dunn drank at least three light beers and three shots between 10.30pm and 2.10am at Barnaby's of America bar before the accident.
Fellow Twitter users were also angered by Ebert's remarks.
One tweeter, @ebertchicago, responded: 'That was in disgustingly poor taste,' while another added: 'Why is this a joke? He is still a person. Have some respect.'
Celebrity gossip blogger Perez Hilton waded in to the row too, branding Ebert's comments 'in poor taste'.
An article on Hilton's blog read: 'We certainly agree that driving after drinking is wrong, we think there's no reason - especially RIGHT NOW - that anyone should be pointing fingers or poking fun at a truly tragic situation.
'Everyone makes mistake, and this is somebody's son. Too soon, Roger.'
But Ebert stuck to his guns, merely retweeting Hilton's article with the comment: 'Perez Hilton's readers agree with me and not with Perez about my tweet on Ryan Dunn.
'He drank, he drove, 2 people died.'
Police said they found Dunn's 2007 Porsche 911 GT3, capable of reaching 190mph, completely engulfed in flames in woodland beside the road.
Last picture: Just hours before his death, Ryan (left) tweeted this photograph of himself enjoying a night out with his passenger Zac Hartwell (far right) who also died in the accident, and another friend
Outrage: The offending remarks by Ebert on his Twitter page. An autopsy is under way to ascertain whether drink played a part in the accident, but the toxicology results have still not been released
Reaction: Bam Margera retaliated on Twitter against Roger Ebert for his comments in the wake of Dunn's death
Dunn's body was so badly burned that he had to be identified by his tattoos, NBC Philadelphia reported.
Dunn was the registered owner of the $100,000 vehicle and was driving at the time, according to police.
Dunn's passenger has now been identified as his frIend Zac Hartwell, who was drinking with him in the bar before the accident.
police reportedly had trouble identifying the body due to the horrific nature of his injuries.
An official report states that a 'preliminary investigation revealed that speed may have been a contributing factor to the accident'.
The Chester County Coroner was conducting an autopsy on Dunn following the crash to determine if alcohol played a role in his death, TMZ reported.
It emerged today that Dunn was charged with a drink-driving offence six years ago.
Patrick Carmody, the Assistant District Attorney in Chester County, told RadarOnline that the Jackass star was charged in 2005.
He told the website: 'In 2005, Dunn was charged with driving under the influence of alcohol and entered a first offender's programme that allowed him to clear his record after a certain period of good behaviour.'
Tyre marks at the scene of the crash show where the Porsche careered off the highway, through a metal guardrail and into the woods.
Pictures from the scene show the charred remains as a tow truck dragged the wreckage from the woods.
Yesterday Johnny Knoxville, the leader of the Jackass gang, led the tributes to his former co-star.
He said on Twitter: 'Today I lost my brother Ryan Dunn. My heart goes out to his family and his beloved Angie.'
He ended the post by saying: 'RIP Ryan, I love you buddy.'
Knoxville later added: 'Please drive safe and wear your seat belt. Ryan Dunn will be missed. God bless.'
Dunn rose to fame as part of the stunt crew for the MTV show Jackass, which ran from 2000 to 2002.
Investigation: Dunn's Porsche was found engulfed in flames in woods beside the road
He was working as a welder and part-time gas station attendant when Knoxville, a friend of Bam Margera through the skateboarding circuit, asked to use their videos, which became an instant hit.
Dunn, Margera, Christopher Raab (known as Raab Himself) and Brandon DiCamillo had started making videos featuring themselves skateboarding and performing stunts under the moniker CKY for 'Camp Kill Yourself'.
Dunn later featured in Margera's Viva La Bam from 2003 to 2006 as well as all three of the Jackass movies.
Fellow Jackass co-stars also paid tribute to Dunn today.
Where the night started: Dunn spent the evening at Barnaby's bar in West Chester before the accident
Stephen 'Steve-O' Glover was too distraught to speak but later tweeted: 'I don't know what to say, except I love Ryan Dunn and I'm really going to miss him.'
Dunn's name began trending on Twitter soon after the news of the crash broke, with fans and celebrities quickly expressing their condolences.
It was Margera's mother, April, who first confirmed Dunn's death by calling into radio show The Preston and Steve Show on WMMR 93.3.
She described him as being like a son to her and said he had even called her on Mother's Day.
A tearful April said: 'We just found out a few hours ago - it is the worst possible news.
'I have not been able to talk with Bam as he is in Arizona but I cannot believe that his friend is dead – I felt like I lost one of my own sons when I heard that Ryan Dunn had died.
'Ryan was a wonderful person, he really was the sweetest and nicest guy - he was like my extra son, everybody loved him.'
Dunn was born in Ohio and moved at 15 to Pennsylvania, where he met Margera on his first day of high school.
April said she is 'worried' about her son Bam, adding that he is 'devastated' by Dunn's death.
Crash scene: Black marks on the road show where Dunn's car skidded out of control
Devastation: Dunn's car span off the road, through a guardrail and into the woods
Crowd: News crews and onlookers arrived at the site today following Ryan Dunn's horrific accident
Tributes: Flower were laid by the side of the road in memory of the reality star who died in the crash
Van Toffler, the president of MTV Networks Music/Films Group, said in a statement: 'We are devastated by the tragic loss of Ryan Dunn – a beloved member of the MTV family for more than a decade.
'He made us all laugh and had the tireless enthusiastic approach to life of your favourite middle school friend.
'Our thoughts and deepest condolences are with Ryan’s family and friends. The Jackass brotherhood will never be the same.'
'He had a long-term girlfriend and she will be absolutely devastated. It’s just so sad we cannot believe Ryan has gone - I’m too upset to say anything else just now.'
Sports car: Dunn pictured in his Porsche 911 GT3 with a female companion on June 12
Police report: The Chief of Police in West Goshen, Pennsylvania, notes the 2007 Porche was discovered 'fully engulfed in flames'
Good Charlotte guitarist Benji Madden said: 'I'm very Sad and Shocked to hear about Ryan Dunn. My thoughts&Prayers are with his Family.'
Reality TV star Brody Jenner wrote: 'Just heard about Ryan Dunn… So sad.. #RIPRYANDUNN.'
Dunn was famously involved in a golf cart accident during the filming of the first Jackass movie during which Johnny Knoxville was injured.
Devastated: Dunn's co-star Johnny Knoxville took to Twitter to express his sadness over the loss of his friend and posted this picture of the star
Grieving: Jackass star Steve-O posted this message on his Twitter page today
He was driving the golf cart with Knoxville as a passenger when he tried to launch the vehicle over a sand bunker. Knoxville was thrown from the cart which then landed on top of him, knocking him out.
Dunn also had a one-season run with a show of his own Homewrecker, which saw him help the victims of practical jokes gain revenge.
He appeared in the Jessica Simpson film Blonde Ambition and NBC's Law & Order: SVU.
Most recently, he hosted Proving Ground on the G4 cable network.
The crew: Dunn (far right) was part of the cast for MTV show Jackass