Mystery man on roof during Boston Marathon bombings

Mystery man on roof: An image of the second explosion also captures a shadowy figure on a roof above the incident. Who is the mystery man on the roof? Consipiracy theorists want to know.

Who's the mystery man on the roof?

That's what the Twittersphere wants to know in the wake of the Boston Marathon bombings.

A photo credited to Suffolk University junior Dan Lampariello shows the instant of the second explosion that occurred near the marathon finish line Monday. The photo went viral in social media, and was broadcast on CNN, ABC, and CBS, among others.

Dan Lampariello told ABC News Monday "I was about 200 feet from the finish line ... right in front of the Mandarin Hotel. My aunt was actually running in the marathon. We were out there to cheer her on. We thought maybe it was fireworks at first, but when we saw the second explosion we definitely knew that something was wrong."

And then the chatter started.

The buzz isn't over the explosion, but over the tiny figure seen on the roof in the upper left.

Can you say Grassy Knoll? Conspiracy theorists around the world are jumping all over this.

Police say they have no suspects yet.  No individual or group has claimed responsibility for the attack. But The Christian Science Monitor and other media outlets reported:

"On Monday night agents from the FBI, the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), and other law enforcement agencies raided a unit in a high-rise apartment on Ocean Drive in the seaside Boston suburb of Revere, according to information posted online by a participating local fire department. Several bags, including what appeared to be a large duffel bag, were removed from the scene. Authorities were mum as to the specifics of their suspicions but confirmed that the Revere search was related to the case."

Boston police also issued a BOLO for a yellow Penske rental van that apparently attempted to access the race course area shortly before the blast. And they are looking for a "black man wearing a black hoodie and a black backpack" who was turned away from a secure area shortly before the bombings. 

In the vacuum of information available to the public, the social media chatter is happy to focus on this photo. But as the speculation continues, a note of reason was posted by Scott Hays on his Twitter account:

"I mean, I'd want to talk to the man on the roof too, but, a big race was going on, I'm sure rooftops provide great views."