A Marine shot and killed two colleagues before turning the gun on himself at the Marine base in Quantico, Virginia late on Thursday night. The first victim was shot in the barracks area of the Officer Candidates School around 11 p.m., then the gunman barricaded himself in a room. The base was put on lockdown, and when authorities entered the barracks early on Friday morning they found the suspect dead of a self-inflicted gunshot wound, and a second victim. Few details are available, but authorities say they believe the shooter was a staff member at the school.