According to the Christian Science Monitor, a photo of a mysterious man on a roof near the explosions at the Boston Marathon yesterday has gone viral as the public and investigators try to figure out exactly who is responsible for the bombings.

The photo shows the moment of the second explosion, but much of the focus on the Internet has been on the figure that can be glimpsed on one of the rooftops on the left-hand side of the picture.

While police haven't identified any suspects yet, several media outlets have reported  that agents from the FBI, the ATF and other law enforcement agencies raided an apartment in Revere, Mass., a town just outside of Boston.

According to Boston.com, police carried several large bags from the apartment, but did not disclose what was in the bags. On its Facebook page, the Revere Fire Department said the search of the apartment at 364 Ocean Ave., was for "a person of interest" in connection to the attacks at the Marathon site, but did not give any more information.

According to the Boston Police Department, the FBI is interviewing witnesses, but there is no one in custody in connection with the bombings.