Surveillance video: The Islamabad hotel truck bombing

The camera didn’t capture the blast — have a look at the size of the crater and you’ll see why — but it caught everything up to that moment, including what appears to be the bomber blowing himself up in the driver’s seat as guards closed in. How’d he manage to set off the truck bomb, then? With “good” luck, apparently. It looks like the flames from the front-seat explosion started a fire in the back of the truck that set off the payload before security could put it out. 53 dead at last count, including two U.S. Marines.

Had the bombmakers had known what they were doing, it would have been much worse. Here’s Danger Room on the significance of aluminum powder being found in the residue:

Devices with a high proportion of metal powder to explosive are termed “thermobaric.” When the explosive goes off, the metal powder at the leading edge of the fireball burns as it contacts the air. With a crude device, the powder simply burns and adds to the fireball. In more advanced weapons, the burning metal produces a sub-sonic shockwave (known as deflagration); the most advanced type produce a detonation (supersonic shockwave) of tremendous destructive power…

The Marriott attack left a large crater, indicating that much of the blast came from a point source. The metal powder seems to have contributed only to the incendiary effects… [A] similar device with enhanced engineering could have leveled the building and caused far worse casualties. Terrorists showed that one of the most secure buildings in Islamabad was still vulnerable to attack, but there was far less damage than there might have been.

The use of gas canisters in the London car-bomb plot last year also suggested intent to build a thermobaric bomb. They’re not just trying to kill people in the immediate vicinity, in other words; they’re trying to take down buildings by boosting the force of the blast, kind of like Tritium does with nuclear weapons if I’m understanding this correctly.

AQ’s being blamed, but less interesting for the moment than whodunnit is who the target was. Reports variously point to the CIA, to Danish intelligence as payback for the Mohammed cartoons, or to the new Pakistani government, which had planned to meet in the hotel at the time the bomb went off — and then changed its plans at the last minute. From the Daily Mail article linked up top:

Interior Ministry chief Rehman Malik did not explain why the prime minister and president decided to move the dinner from the Marriott to the prime minister’s house but said the decision was kept secret.

‘Perhaps, the terrorists knew that the Marriott was the venue of the dinner for all the leadership where the president, prime minister, speaker and all entire leadership would be present,’ Malik said.

‘At the eleventh hour, the president and prime minister decided that the venue would be the prime minister’s house. It saved the entire leadership.’

Curiously enough, according to Dawn, a patrol van carrying police commandos stationed outside the Marriott was removed at around 4:15. Was that because the government meeting had been canceled, or is there a darker explanation? To wit, your exit question: Who would have had intimate access to the Pakistani leadership sufficient to know its whereabouts and an interest in sharing that info with jihadis to help them carry out a decapitation strike? Hmmmmmmm.