Two Marines were shot and killed Thursday at the Quantico Marine Corps base by a third Marine, who then killed himself.
NBC News reported that the three Marines knew each other and may have been involved in a "love triangle." Two of the Marines, including the shooter, were men, while the third was female.
The Washington Post reported that the suspected shooter was a staff member at the school.
Authorities learned of the initial shootings just after 11 p.m. when they found one of the victims, a spokesman for Quantico told CNN. The suspect, who was in a barracks near the first shooting, was then surrounded.
Hours later authorities entered that barracks and found the shooter dead. Another female victim was nearby, NBC reported.
NBC reported that all three Marines were enlisted and were instructors at the school just south of Washington, D.C.
—This story was updated at 7:05 a.m.