A federal employee is in custody for allegedly staging an "active shooter hoax" that prompted a lockdown Tuesday morning at New Jersey's Joint Base McGuire-Dix-Lakehurst, one of the nation's largest military bases, the state's acting U.S. attorney said. The lockdown at the U.S. military base in Burlington and Ocean counties started just before 11 a.m. A Facebook post from the base urged all personnel at the facility to seek shelter. The lockdown was lifted just before noon, and the base later said it had received a report of an active shooter at the military installation. Charging documents say Brittingham sent a text message to an unnamed person around 10:15 a.m. warning of an active shooter, CBS News reported. Joint Base McGuire-Dix-Lakehurst is the nation's only military base with service from the Air Force, Army and Navy.