A U.S. Navy sailor opened fire on three civilian Defense Department employees on the Pearl Harbor Naval Shipyard in Hawaii on Wednesday, killing two and wounding the third before turning the gun on himself.

“I know that no words will convey the full measure of sorrow from today’s tragedy. This loss will be felt throughout our shipyard ‘Ohana, greater shipyard & NAVSEA family, submarine force, and the Navy as a whole.” Shipyard Commander Capt. Greg Burton said.

While the sailor’s identity has yet to be revealed and there as of yet no indications of a motive, some details regarding the incident have begun to emerge. The sailor, according to U.S. Navy personnel, was reportedly assigned to a submarine that docked in Pearl Harbor, just days ago, in preparation for the 78th anniversary of the Japanese attack on the same Naval facility that thrust the United States into the second World War. It appears that the unnamed sailor was likely assigned to the USS Columbia (SSN-771) — a Los Angeles class, nuclear powered fast attack sub.

“We have no indication yet whether they were targeted or if it was a random shooting,” Rear Admiral Robert Chadwick said. He went on to say that the wounded man, a 36-year-0ld civilian shipyard worker, is currently in stable condition.

At approximately 2:30 p.m. local time on Wednesday, Joint Base Pearl Harbor-Hickam was ordered on lockdown following numerous reports of an active shooter on the installation. The unnamed sailor opened fire at the facility’s Dry Dock 2. This may mean that all three victims were likely shipyard workers.

It seems that security forces did not arrive until after the shooting stopped, as eyewitnesses reported seeing the man shoot three victims before turning the gun on himself. The base remained on lockdown for approximately 90 minutes as security forces secured the area and confirmed that there were no other shooters.

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“I kind of recognize that as gunshots,” one witness, who asked not to be named, said. “I looked out the window, saw three people on the ground. I looked out in time to see the shooter … shoot himself.”

Governor of Hawaii David Ige took to Twitter to thank the White House for immediately offering assistance and going on to say, “I join in solidarity with the people of Hawaii as we express our heartbreak over this tragedy and concern for those affected by the shooting.”

Bringing a personal weapon on base is not authorized on Joint Base Pearl Harbor-Hickam, according to Rear Admiral  Chadwick, who could not confirm what type of firearm was used in the attack. It seems likely that it was a pistol, as that would be the easiest to conceal on the way into base.

The Navy has launched an investigation into the incident, with local support being provided by detectives out of Honolulu’s police department and the city Medical Examiner’s Office.