The problem is that if those "leads" are made public and point at specific people, then some people will let their outrage over what happened blot out all doubt that the "leads" are not conclusive evidence and take what they believe to be justice into their own hands.
As a counter example look at the arab guy. You can read about him in wikipedia and somewhat online (its intentionally not being discussed much by the media). Immediately after the blast a bunch of people tackled an arab dude for the crime of "running while Arab" and turned him over to the cops who tossed his apartment upside down. The latest I've heard was an official police spokesman said the arab dude had nothing to do with the event other than being another victim.
I would say this is an absolutely worst case heat of the moment outcome. Can't claim its unrelated or irrelevant. Its a sad outcome that lots of americans automatically equate being arab with being a criminal, and its sad he got tackled after nearly being blown up, and its sad the cops trashed his house, but in the long line of human injustice, its not that bad, no one shot him or lynched him or ruined his reputation.
In a somewhat slower paced, more methodical, less emotional situation like looking at pictures of backpacks online, I think the likely outcome compared to the poor arab dude would be immensely more likely to tend toward rational wise justice than uncontrolled rabid injustice.
Sure, the outcome is more likely to be rational for each single person, but when it's published on the internet, there are suddenly potentially millions of people involved, some of which are certain to be not rational and wise at all...
