On a video posted to YouTube.com this summer, a man speaking Egyptian-accented Arabic instructed viewers how to convert a remote-controlled toy car into a bomb detonator. The 12-minute lesson was referenced on the popular video-sharing website under the search terms “detonator from a distance”, “suiciders” and “martyrdoms”.“A detonator could save one who wants to be a martyr for another day, another battle,” the man told viewers, according to federal prosecutors. Last month, authorities identified the instructor as Mohamed Ahmed, 24, a graduate engineering student at the University of South Florida. An Egyptian national, he’d been stopped for speeding in South Carolina on August 4, then arrested with a fellow student for allegedly carrying four pipe bombs in the trunk. Now as the criminal prosecution continues, questions remain not only about the men’s intentions, but also about the way the popular video-sharing website may have been used to spread bomb-building know-how. Representatives of You Tube declined to answer questions last week regarding their handling of the detonator video. They offered instead a generic statement, saying that videos are removed once viewers flag them as inappropriate and the company determines that they violate its standards. The company would not say how long the detonator video was available on the site; how many times, if any, it was viewed; or whether the company took it down as part of normal policing based on viewer tips or whether it was removed at the FBI’s request. The incident comes amid growing questions regarding what role a company such as YouTube has in controlling its content. John Palfrey, a professor at Harvard Law School who specialises in Internet issues, said it’s “pretty clear” under US law that companies such as YouTube do not bear liability for items third parties post. But, he said: “As more and more important information goes online, and the impact of posting it there continues to grow, some people are starting to question whether we have the right policy.” Mohamed and Youssef Megahed, 21, were stopped by police in Goose Creek, SC, who said their 2000 Toyota Camry was traveling 60 mph in a 45 mph zone. In the trunk, the deputy found four PVC pipes containing a mixture of fertilizer, kitty litter and sugar; 20 feet of fuse cord; and a box containing .22-caliber bullets. They also confiscated a laptop computer. The FBI classified the mixture in the pipes as “explosives”, although it has also been characterised as “low grade”. Mohamed called it fireworks. The laptop’s contents proved just as interesting to police.