UPDATED: Gunman, Two Victims Dead in Quantico Shooting

Three are dead in related shootings at the Officer Candidate School at Quantico late Thursday night, including two victims: a man and a woman, and the shooter, all of them Marines.

"The shooter, an active-duty Marine, has been pronounced dead of an apparent self-inflicted gunshot wound by law enforcement at the scene," First Lieutenant Agustin Solivan said. "Two other victims, also active-duty Marines, were pronounced dead at the scene."

Officials at Quantico were alerted of the first shooting at 10:30 p.m. Thursday, prompting a lockdown of the Marine Base, which police announced using a public address system.

Outside the military base Prince William Law Enforcement surrounded the area.

Law enforcement officers found that the shooter had exited one building of the Candidate School and was in a nearby barracks with the room barricaded.

When law enforcement officers entered the room two hours later, they found him dead of a self-inflicted gunshot wound. They also found the second victim with him, a female, who was also fatally shot. Both victims were Marine personnel assigned to the school.

The suspect was also a staff member at the Officer Candidate School, according to Capt. Eric Flanagan, a Marine Corps spokesman.

According to Base Commander Col. David Maxwell, the incident was isolated to the Officer Candidate School, and everyone else at the school and base is safe and without injury.

"As we take care of our Marines and their families that are dealing with this tragedy," Maxwell told reporters, "I'd also ask for the support of our neighbors, the community, and their thoughts and prayers as well for our Marines who have lost their comrades-in-arms."

Prince William County Police assisted the Provost Marshal's Office in response to the tragedy, according to Solivan, and Maxwell said their quick response time helped resolve the situation.

Quantico is no longer under lockdown and has returned to normal operations, although the incident is still being investigated and the shooter's motives are not yet known.