No motive is yet known for last week’s Pearl Harbor Naval Shipyard shooting tragedy, which appears to have been a random act of violence in which the sailor who fatally shot two civilian workers and himself did not plan his actions ahead of time, shipyard commander Capt. Greg Burton said in an “All Hands” message sent out today.

Machinist’s Mate Auxiliary Fireman Gabriel Antonio Romero of San Antonio, Texas, an armed watchstander on the attack submarine USS Columbia, shot three civilian workers Dec. 4 and then turned a gun on himself while the sub is in dry dock 2 for a major overhaul.

“The investigation continues, but there is currently no known motive and no information to indicate the sailor knew any of the victims,” Burton said.

Burton said Romero, 22, who is not identified by name in the letter sent to shipyard workers, did not appear to have a history of violent behavior.

“He had not been to court martial and was not facing non-judicial punishment,” Burton said. “Based on a review of records, he had not been scheduled for nor taken any anger or stress management classes.”

Burton confirmed that Romero used an M-4 rifle and 9mm pistol in the shooting.

“We may never fully know everything that happened,” Burton said. “However, there are some initial reports that I have received and as I promised, will share with you what I have learned.”

Burton said that “stakeholders” have begun implementing changes and reviews to ensure the shipyard force of over 6,000 is safe and sailors are receiving care.

“Submarine Force, U.S. Pacific Fleet shared that all of its submarine commanding officers have reviewed the screening of each qualified watchstander who is authorized to carry weapons and has reiterated the need for supervisors to continuously assess the fitness for duty of their sailors to ensure they identify and address those who pose risk.”

The two dead shipyard civilian employees were Roldan A. Agustin of Hawaii, 49, a shop planner (nondestructive testing); and Vincent J. Kapoi Jr., 30, a metals inspector apprentice.

Agustin, a retired Hawaii Army National Guard staff sergeant, was deployed twice — once to Afghanistan and once to Kuwait — as an aviation maintenance specialist.

A third worker, shipyard apprentice Roger Nakamine, 36, was wounded, but has since been released from The Queen’s Medical Center. The Associated Press reported that the shooting transpired in a 23-second span and Romero was dead when authorities arrived.