The Boston Marathon bombing investigation, now in its third day, is not just the largest crime scene in the city's history — it's the most crowdsourced terror investigation in American history. With the FBI, the ATF, and Boston law enforcement soliciting videos, cellphone pictures, and anything that could lead to the capture of whoever set off those pressure cooker bombs, the plea has more or less turned the interested and the Internet into amateur investigators armed with what we know the remains of the bag and the bomb look like. On Reddit, where they can now apparently track murder by way of Google Maps and where some of the most detailed information on the Boston case has surfaced publicly, the FBI's plea for info has spurred the "Find Boston Bombers" subreddit, with all kinds of analysis. But here's the find they're most excited about: They've found a photo of a man with a backpack that has straps which resemble what federal officials believe is the detonated backpack. (Update: Authorities appeared to have a suspect — follow here. Update 2: Now they actually have a suspect — two of them — and Reddit is on the case.)

We have obscured the man's face because, well, the only suggestion of a connection to the bombings comes from people on Reddit who have been looking at photographs: 

And one more angle, showing extreme close up of the straps. 

Again, we can only vouch for the image of the detonated bag, which the FBI says contained one of the pressure cooker bombs. There are no details on where the image of the man in the blue jacket came from, or at what time it was taken during the marathon, or the location— the only reference we have is that it trickled down from social media and Flickr, and down to sites like 4chan and Reddit. Redditors, to their credit, haven't been shy in voicing the skepticism and concern with pinning this terror attack on an innocent man:

The Atlantic's Alexis Madrigal has a compelling point about how this Internet vigilantism movement is troubling, and could end up in people being unfairly singled out. And yes, there's a deep, and problematic potential of that happening. The blue sweater picture isn't the only other photo popping up however, like this one who one poster believes could be smuggling a pressure cooker bomb because of the shape of his backpack:

Internet sleuths believe this a photo of that same man without his backpack (we can't tell one way or another): 

And this, one, which we sorta have no idea why things are being circled:

Reading through the amateur forensics feels like an intense and puzzling game of Where's Waldo.  But it's a byproduct of what you get when the FBI asks the public for help. Jittery nerves lead to things like the New Yorkers who reported 77 suspicious packages in the wake of the Boston bombings, and multiple incorrect Chris Dorner sightings in February. And the blue robe man, along with the pressure cooker backpack man, are all tips—tips that part of the thousands the FBI receives. As The Washington Post reported:

[Richard] DesLauriers said cooperation from the community will play a key role in the investigation. He said the range of suspects remained wide open, but by midday Tuesday more than 2,000 tips had been received.

(Click here for the latest updates on Day Three, and click here for complete coverage of Boston.)