Just a couple of weeks after a pipe bomb was detonated outside of a San Diego Fed Ex building in the early morning hours a federal courthouse has been a targeted by a bomber with a similar M.O. leading some to believe there is a connection. From Sign on San Diego:

SAN DIEGO – A pipe bomb or series of pipe bombs exploded at the Edward J. Schwartz Federal Courthouse downtown early Sunday morning, sending shrapnel into a courtyard and to the eighth floor of a building across the street.

Two guards with the Federal Protective Service, who were inside the building, called authorities when they heard the explosion at 1:40 a.m. The guards, who work for a federal agency that is part of the U.S. Department of Homeland Security, were not injured.

Firefighters, police, FBI and Bureau of Alcohol, Tobacco and Firearms and Explosives agents arrived minutes later to find the front door shattered and the lobby of the building damaged.

The FBI announced Sunday afternoon that the courthouse, on Front Street near Broadway, would be closed Monday.

The cause of the blast is believed to have been a bomb or bombs that detonated simultaneously and caused a single explosion, said Keith Slotter, FBI special agent in charge of San Diego. No threats were made and no one has claimed responsibility, an FBI spokeswoman said.

Before the investigation began, San Diego Metro Arson Strike Team and ATF bomb investigators searched the area to make sure there were no other explosives.

Early Sunday morning, about 40 agents combed the courtyard in front of the courthouse, Front Street and a courtyard on the other side, using evidence markers and spray paint to locate debris from the blast.

“The damage from the shrapnel didn’t stay concentrated just in front of the door,” Slotter said.

One piece of shrapnel lodged in a window about eight stories up the AT&T building that faces the courthouse. A damage estimate was not immediately available.

Authorities believe the device or devices were left outside the building’s front door shortly before being detonated.

Darrell Foxworth, an FBI spokesman, said surveillance tapes from the cameras that record activity in front of the building will be examined.

Front Street was closed between Broadway and F Street until just after noon Sunday while investigators collected evidence. That evidence will be sent to an FBI laboratory in Virginia, where bomb experts will analyze it, Slotter said.

At the time of the explosion, there were not many people near the building, which is at least a block from the nearest nightclubs in the Gaslamp Quarter. Slotter said there were vehicles passing by when the explosion occurred, but no reports of injuries.

Officials said they don’t know if the bombing is connected to a pipe bomb that exploded at a Federal Express building April 25.

With a healthy amount of snark some blogs on the right are linking this bombing to the kind of activities William Ayers and The Weather Underground used to partake in. Obama jokes aside, the bombings are similar enough for us to assume they’re connected and the targets, a corporate office and a courthouse, seem likely to draw the ire of “revolutionaries” with a leftist bent.

Pipe bombs are becoming all the rage with “progressives.” How long until someone is killed by one?