The investigation remains in the early stages, and the public is clearly pouncing on any sign of a lead. Reports of a police search at a Revere, Mass. condo complex between five and six on Monday night lit up Twitter. However, it's unclear if the search was related to a bombing or not.

The Other Devices

Soon after the initial explosions, Boston Globe photographer David L. Ryan reported that he heard but did not see a third explosion, and Boston police were scrambling to contain the scene. "There were two booms heard from near the finish line" reports the AP. A spokeswoman at the Fairmont Copley Plaza Hotel, close to the explosion, says that it was around two blocks away, while The Boston Globe said that police were conducting a "controlled explosion" on the 600 block of Boylston Street.

Over the course of the afternoon and evening, police say they found five additional devices along the marathon route, though a police source later said it was unclear if they were actually bombs. That number does not include numerous reports of suspicious packages around Boston and neighboring cities. The Boston Globe reported another device found near Harvard, and there was a bomb threat phoned in near the Financial District. There were also reports of undetonated devices being found as far away as Newton, though local police have denied those claims. Again, the Journal walked back its initial claim of the five unexploded devices.

And then there was the library fire, which had a whole back-and-forth narrative of its own.

Here's an updated interactive map of the at times confounding activity, including multiple reported incidents about unconfirmed devices, fires, and all the explosions throughout Monday, both alleged and confirmed, for a sense of scale in downtown Boston and beyond — even as the day seemed to settle on the two explosions near the finish line:

The FBI said on Monday evening that local police and federal agents would sweep the entire length of the course to look for evidence and additional devices. Meanwhile, the Navy has sent an Explosive Ordnance Disposal team to help with the effort.

The Pictures and Video of the Explosion

Here are a couple of many images to flow in from social media early on:

Explosion at coply twitter.com/Boston_to_a_T/… — Boston to a T (@Boston_to_a_T) April 15, 2013

And one more:

Just heard that bombs went off at #boston marathon finish line twitter.com/chanyasulkit/s… — Chris Chanyasulkit (@chanyasulkit) April 15, 2013

Here is perhaps the most shocking, dramatic, and up-close video from the bombings, via the Globe:

Here is the moment of impact for the first of the two confirmed explosions, by way of Twitter's Vine, right near the sidewalk (scroll down for video of both):

We're going to link to these next two shots (WARNING — they are graphic) since they show the chaos and some of the injuries, and there are a few very graphic images that have been uploaded to Reddit. NECN's Jackie Bruno reports that the injuries there are gruesome:

I saw people's legs blown off. Horrific. Two explosions. Runners were coming in and saw unspeakable horror. — Jackie Bruno (@JackieBrunoNECN) April 15, 2013

To be sure, this is a time to be good to each other. Because there are as many unconfirmed reports and speculative ideas (CBS News reported that certain terrorist target areas are being monitored in Boston, and the Secret Service set up a perimeter around the White House) as there are graphic images. There are amputations. Here are some of the first photos to hit the AP wire (WARNING — it is graphic):