Where did the explosions come from?

http://www.youtube.com/watch?v=M5FQfBHgLlo

Something of a timestamp......In this You Tube video, the news reporter (at about one minute in) says "The woman who sent these pictures exclusively to 7news said an hour passed between the two".

Much can happen in an hour. The owner or owners of the bags may have left with the bags long before the device was detonated. There's no reason to think the bags were even there immediately prior to the blast. The idea that this is a photo of the bomb is looking more and more speculative.

This photo appears to show the metal grate at the base of the tree. If I understand how the bombs were made, they use glue and metal (this case BBs) to line the inside walls of the pressure cooker. The bomb might very well have been placed directly on the metal grate. This shrapnel could be the part of the bomb that was facing down towards the grate and been embedded or stuck (due to the glue possibly?) in the grate when it exploded. If the bomb was directly on the grate this allowed the FBI to remove the grate as evidence where as they would have had to cut and dig up the sidewalk at the other blast site.

Added: Also the back pack could have melted and cause this piece to stick to the grate. Or it could just be laying there not stuck.

I don't find it odd that bags might have been left behind after the bombs went off. If someone already had their bag down when the blasts went off, the last thing they might think about is picking up their bag before running way. People might also drop bags to run faster.

If the FBI removed the tree because he leaned against the tree then this would support the idea he might have put the bag down near the tree.

There is news footage of two separate witnesses claiming they saw a trash can explode at the second bomb site.
Nothing has been reported about this as far as I am aware (anyone have anything specific?), besides the bombs being in backpacks.

No-one is reporting it, but it was on a news report?

Pete Tar said:

No-one is reporting it, but it was on a news report?

Click to expand...

On ABC news actually, the had a guy saying flat out he saw the trash can explode at the second site. Not sure where the second interview was...I'll try to find a link to them

I'm saying, read anything you find to be a credible source in the bombings. Does it say the second bomb went off in a trash can? I'm betting most likely not; none seem to mention that detail. But 2 witnesses mentioned seeing it and that's all that was ever reported/released about the bomb's location.