[Obama_Is_Sabotaging_America]

Wouldn’t the grate been blown up, out and away from the explosion? Or are you saying the bomb might have been temporarily stowed away there?

[gore_sux]

I think the explosive was relatively low powered and did not have enough ummff to blow a heavy porous grate with a bunch of people standing on top of it. This theory makes perfect sense with regard to all of the lower leg injuries seen. This also means it is highly unlikely the perp was even in the area at the time unless he wanted to get a good look at his handiwork.

[matt1234]

Wouldn’t the grate been blown up, out and away from the explosion?

Yes, quite possibly. But look at the "before" picture. There are approx. 10 people standing on the grate.

Anyhow, I offered the tree well as merely a possiblity: one of many.