Investigators have identified two “principal protagonists” in the botched terrorist attacks in London and Glasgow and are trying to establish how the other detained suspects fit in, a British security official said on Saturday. The two principal suspects are almost certainly the two men arrested after crashing their Jeep into the terminal of Glasgow airport: Bilal Abdulla, a British-born Iraqi doctor who was formally charged on Saturday, and a man known both as Khalid and Kafeel Ahmed, an Indian engineer who is being treated for the serious burns he sustained after driving a burning Jeep into the airport here last weekend. The British official suggested that it was becoming clearer that the other suspects—five men and one woman, all medical personnel—played a lesser role. Now, he said, “it’s a matter of trying to fill in the gaps.” On Saturday, Bilal, a 27-year-old Sunni described by an acquaintance as angry over the US and UK presence in Iraq and over the increasing power of Shiites there, appeared in criminal court in London wearing a white T-shirt and was charged with conspiring “to cause explosions” endangering many.The first attempted attack involved two cars, both loaded with gas canisters, gasoline and nails in central London in the early hours of June 29. The second was at Glasgow airport a day later. Bilal, who has been in and out of Britain in the past few years, graduated from medical school in Baghdad in 2003. He lived in Cambridge at various times between 2001 and 2005. Shiraz Maher, a writer who says he was once a member of the radical group Hizb ut-Tahrir, said he knew both Abdulla and Kafeel when they lived in Cambridge. He said they socialised at the Islamic Academy. At the time, Kafeel was living in a room in the academy—a suburban home also used as a prayer hall and centre for promoting an Islamic education, Maher said. British media have reported that Kafeel, who early in the investigation was mistakenly thought to be a medical professional, was reportedly a student at Anglia Ruskin University in Cambridge. They have also reported that Sabeel Ahmed (26), who was arrested in Liverpool, is his brother, and spent time in the city during this period. Those reports have not been confirmed. “Kafeel was quieter than Bilal,” said Maher. “.but he has an adrenaline personality. If someone said ‘let’s go bungee-jumping or parachuting’ he would have gone.” Another suspect, Mohammed Asha (26), is thought to have spent six or seven weeks working at Addenbrooke’s Hospital in Cambridge. In 2005, when he was working part time at Staples, Bilal was living around the corner from it, in an apartment.