I think the reporter leaking the suspect had the description told to him slightly wrong, after seeing a new pic with the Middle eastern guy standing at the EXACT spot the bomb went off, and also wearing a black shirt and white cap, what are the chances.He walks up from the back, stands at the spot the bomb went off (part where he is closest to the road), takes off his rucksack, places it at his feet, waits there for 30 mins or so the people who may have noticed him put the bag on the floor have moved on, then walks away.