Three are dead after a shooting at Quantico Marine Corps Base in Virginia on Thursday night. All the victims were Marines, including the shooter, who took his own life. Early reports indicated that after the first person was shot around 11 p.m, authorities and the gunman -- believed to have been a staff member at the base’s officer-candidate school -- engaged in a standoff, with the suspect barricaded in the barracks. When the authorities finally entered the barracks early Friday morning, they found the shooter and another victim dead inside.

NBC News reports:

"The assailant and both victims, a man and a woman, were staff members at the school and not students, a senior defense official said. The official called the incident "isolated," adding: "There was nothing random here."'

"The names of the dead were being withheld for 24 hours pending notification of next of kin."

"Military police and Prince William County, Va., Sheriff's Department officers responded to a report of gunshots around 10:30 p.m. local time and were on the scene within five minutes, base commander Col. David W. Maxwell said at a press conference on Friday."

"They found one Marine dead and the shooter inside the barracks, a Marine official said. At 3 a.m., officers entered the barracks and found two more bodies, including that of the shooter, the official said. The three, all active duty Marines, were pronounced dead at the scene."

Updated reports Friday morning say that authorities did not fire any shots and did not hear any shots fired, and there was no standoff or barricades.

"Why officers hesitated before entering the barracks remained unclear Friday morning."

The assailant appeared to have died from a self-inflicted gunshot wound, according to base officials.

At this time it is believed that a "relationship dispute" was the motive behind the shooting, according to a Marine official.