British security officials told ABC News that they believe they have recovered the body of one of the people responsible for the terrorist attack that killed dozens of people and injured hundreds more in a series of explosions on the London subway and a bus.
Police believe that at least one of the people killed in the explosion at the bus was one of the bombers, though they have not confirmed it yet. According to eyewitness accounts, after the bus driver announced that the bus was being rerouted because of police activity, someone was seen on the top floor fiddling with a bag, and shortly after that the explosion went off.
Investigators believe it was not intended to be a suicide bomb and the bomb went off earlier than expected, the officials said.
Police also have recovered what they believe are the remnants of timing devices on the subway explosions, leading them to believe they were not suicide bombs but explosives planted in packages or bags and left behind.
British police today said that they had recovered two packages that they at first thought were unexploded devices. The packages were exploded purposely by the police to see what they were and turned out not to be unexploded bombs but just packages that had been left behind.
The bomb parts and timing mechanisms should provide important evidence that could help determine who was behind the attacks, sources told ABC News.
Officials now believe that all the bombs on subway cars were detonated by timing devices. Earlier today, British investigators had believed that the bomb on the bus was the work of a suicide bomber, sources said.
Who Is Responsible?
The London bombings are similar in many ways to the coordinated blasts on Spanish trains in Madrid 16 months ago that killed 200 people.
The most important piece of evidence in Madrid was a backpack that was found in the rubble. A cell phone inside had been wired as a bomb detonator, and the phone led police to the terrorists. They were able to track where it had been sold, who had sold it and who had bought it.
Police say twice in the last three years they have disrupted plans to attack the London subway system.
High on the list of suspects in Thursday's attack is the same man who has been terrorizing Iraq -- Abu Musab al Zarqawi. Officials say he and Osama bin Laden have talked of expanding attacks to Europe and the United States and have been recruiting people in the Islamic world and western Europe to carry out the attacks.
The only claim of responsibility came Thursday on an Islamist Web site, posted by a previously unknown group. The site claimed the attacks on London were carried out because of the presence of British troops in Iraq and Afghanistan.
When the claim first appeared, some officials reacted with skepticism, but police now say they are taking the claim seriously, because of other intelligence that has been developed.