The office season 1 episode 1 watchepisodes
Most, if not all, of the SWAT guards were killed by Anslo's mercenaries and all other employees were taken hostage during this takeover. He then managed to set a trap and get the FBI to bring Red into the blacksite, right before infiltrating the facility with his mercenaries. Anslo Garrick, mostly likely due to a leak, determined the location of the Post Office. The other incident was when Anslo Garrick had taken over the blacksite in an attempt to ex-filtrate (extract) Reddington. It was later implied that the guns and passports were planted by Reddington and Tom was innocent. During this time, Liz is forced to track down Gina Zanetakos to prove her husband's guilt or innocence, while the FBI tries to deal with the possible breach, as this placed Elizabeth Keen under heavy suspicion. The first being when the FBI detains Tom Keen on suspicion of being a foreign agent, due to a collection of multiple passports and a gun linked to the killing of a Russian defector being found hidden in the Keen home. There are a great number of special agents, analysts, and crime scene investigators in the Post Office providing support teams. The entire facility is guarded by the FBI Special Weapons and Tactics Teams (SWAT), Hostage Rescue Team (HRT), and FBI Police. The facility is occupied by the task force working with Red to bring down targets on the The Blacklist.