With the FBI releasing only sketchy details about the failed attempt to bring down the Northwest flight 253 in Detroit, many counterterrorism officials and experts caution against hasty conclusions. "This was clearly an attempted terror strike, but it's too early to say whether this guy was a lone, self-motivated terrorist or a part of a larger plot," says one counterterrorism official. "We obviously have to assume the worst, and investigate this thing down to the smallest details."

Authorities say Umar Farouk Abdul Abdul Mutallab, a Nigerian native living in London, tried to set alight incendiary mixture strapped to his leg, but instead set himself on fire. He was overpowered by passengers before he could do any further damage. Abdulmutallab has reportedly admitted links to al-Qaeda; he also claimed the plot originated in Yemen. (See an Obama bin Laden family photo album.)

It isn't uncommon for would-be terrorists to claim an Al Qaeda link where one doesn't exist, but counterterrorism experts say several aspects about the Detroit point to a pattern:

1. The Timing: That the attack took place on Christmas Day is especially suggestive, says Georgetown University terrorism expert Bruce Hoffman. "It's worrisome, because it fits into the jihadist vision of a war between Islam and Christianity," he says.

2. The Technique: Officials say Mutallab tried to set off the incendiary mixture as the plane was on its descent to Detroit. This suggests he was not merely trying to kill the passengers and crew, but was probably hoping to make the plane crash in a populated area. The technique also has parallels with "shoe bomber" Richard Reid's failed attempt to bring down American Airlines Flight 63 just three days before Christmas in 2001.