Originally Posted by Matt 26z

The lack of a suicide bomber probably means this isn't Islamic extremist terrorism.

The 12 second delay between the two bombs is interesting. That could mean they used a cell phone to detonate the first one, waited for the sound of the explosion to reach them and then called in the next one. So you figure a couple seconds for it to register with the bomber that he's hearing the explosion and then another five seconds to end that call and make the next call (assuming it's on speed dial). Now you factor in the speed of sound and you've got an approximate radius of where this person was at.