[Old Teufel Hunden]

"They certainly are not spectators, if they can't be identified as known law enforcement at the scene I would find them extremely suspicious."

Let's assume these guys are "persons of interest". Let's even assume they are the bombers. They have baseball caps and dark sunglasses on. We have really no way of identifying those guys. There's no facial recognition software that could be used. I really believe this is a useless endeavor because I don't see how they are going to be able to track the bombers down through these pictures.

[FlJoePa]

You don’t need facial recognition software. If someone really thinks they are “of interest”, you put their pictures on the local news in Boston and ask people to call if they know who these guys are. They’d get dozens of calls.

[outpostinmass2]

I have seen worse pictures of bank robbers who were caught because somenone recognized them from the pictures.