CAMP PENDLETON -- Navy officials said Thursday that a 29-year-old gay sailor was shot and killed as he stood guard at Camp Pendleton, but they said he did not appear to be the victim of a hate crime.

Capt. Matt Brown, spokesman for Commander Navy Region Southwest, said another Camp Pendleton-based sailor is in custody in connection with the killing of Seaman August Provost of Houston.

A preliminary investigation indicates that Provost was targeted because he was the guard on duty at the Marine Corps base, not because he was gay, Brown said.

"Regardless of the person standing watch in that sentry station, it's very clear to investigators this crime probably would have been carried out in the same way," Brown said.

However, he said investigators were not certain of a motive in the killing and would continue to investigate "aggressively," not ruling out any possibility. The suspect's name was not released Thursday because he has not been formally charged.

Democratic U.S. Rep. Bob Filner of San Diego, chairman of the House Veterans Affairs Committee, on Thursday asked the Defense Department and Marine Corps to determine whether the killing was a hate crime.

Filner's call for an investigation came after leaders in the gay community asked him to intervene.

Nicole Murray-Ramirez, chairman of the San Diego Human Relations Commission and a longtime gay activist, said Provost's family told her that personnel on the base had been harassing the junior sailor.

Ben Gomez, president of the San Diego chapter of Veterans for Equal Rights, said he also has heard from active-duty members of the military that Provost's death was a hate crime.

Provost joined the Navy in March 2008 and was transferred to Camp Pendleton in September 2008 after completing basic training in Illinois, Navy officials said.

Kaether Cordero, 18, of Houston said he had been in an off-and-on relationship with Provost for several years. He said Provost's friends in the Navy knew he was gay.

"He didn't mind if people knew; I knew his friends in Illinois knew about me," Cordero said. "All his friends liked him in Illinois; they all went out and had fun."

When Cordero last spoke to Provost a few weeks ago, the sailor hadn't mentioned any harassment. But Cordero said he since has learned from Provost's sister that some fellow sailors had been giving him trouble.

He said he can't understand how anyone could hurt Provost.

"He was very nice; he wasn't the type to go into anything with a bad attitude," Cordero said. "If there was an altercation going on, he would be the type to walk away."

Provost's body was found Tuesday by the guard who came on duty to relieve him at 3:30 a.m., Brown said. The guard shack is on the west side of Camp Pendleton, where Provost's approximately 500-person Assault Craft Unit Five is based. Provost, armed with a revolver, stood watch over the compound's approximately 30 Hovercraft, and also watched for fires, Brown said.

The suspect in the killing is linked by physical evidence and his own statements, Brown said. He declined to say whether the man was in Provost's unit, and said that if the two knew each other, it was "peripherally." He would not say what the suspect had told investigators, but said he was cooperative.

In addition to shooting Provost, the killer also set a fire in the guard station, an obvious attempt to destroy evidence, Brown said. He declined to confirm reports that Provost's body had been burned.

An autopsy has been performed, officials said, though a cause of death won't be determined until toxicology results are available in several weeks.

Brown said investigators have not determined whether a robbery or any other crime took place. Investigators expect to release more details in the next few days, but still have many people to interview because Provost had many friends and shipmates, he said.

A man orginally detained as a "person of interest" in the crime has been released and is no longer considered connected, Brown said.

Brown called Provost a "rising star," who was looking forward to more training and his first deployment. He said Capt. Ed Harrington, the commanding officer of Provost's unit, had been in touch with the sailor's family in Houston three times to give them support and updates.

The Navy has made grief counselors available to Provost's fellow sailors, Brown said.

"We all share in this grief and sense of loss," he said.

Call staff writer Sarah Gordon at 760-740-3517.

Call staff writer Chris Nichols at 760-740-5426.

The Associated Press contributed to this report.

RELATED STORY:

CAMP PENDLETON: Foul play suspected in sailor's death