CNN The Situation Room April 22, 2013 21:13:00
His phone apparently, takes a cell phone photograph as best they can tell, and 30 seconds before the first blast apparently is on the phone speaking to someone. it's not clear who. at that point, then you see the first explosion take place further up the way, right up here, and this is a short distance to the second explosion. for 18 seconds he's been on the phone. the first explosion occurs. he pauses. remember, there was a 12-second pause, and 12 seconds after this, they say, he has now walked away, leaving his backpack behind. and 10 seconds after he walks away, wolf, is when the second bla...
Source: archive.org