What was the explosion everyone heard about 4 PM yesterday afternoon while a 'suspicious package' incident near the Pentagon was being investigated by several police agencies? Appears the suspicious object was, in fact, an explosive device and either detonated while being moved in an explosion containment vehicle or was detonated at a secure site in South Arlington. I can't determine which. Suspicious object was not a box full of discarded trash as has been reported elsewhere. Police were very concerned about the possibility of a second bomb hidden near the first.