SAN DIEGO, May 5 (UPI) -- The U.S. federal courthouse in San Diego remained closed Monday while authorities collected evidence from Sunday's pipe bomb explosion.
The blast by one or more explosive devices shattered the building's front door, damaged the lobby and also sent shrapnel flying into a courtyard and a building across the street, The San Diego Union-Tribune reported Monday.
A spokeswoman for the FBI said no threats had been made and no one has claimed responsibility for the blast.
Authorities said they believe the explosive devices were left outside the building's front door shortly before being detonated about 1:40 a.m. Sunday. Experts were examining surveillance tapes from cameras that record activity in front of the building while evidence collected at the scene was sent to an FBI laboratory in Virginia, the Union-Tribune said.
Officials said they don't know if Sunday's bombing is connected in any way to a pipe bomb explosion April 25 at a Federal Express building.
