Updated at 6:00 p.m. ET: Four U.S. Marines were arrested after allegedly assaulting a gay man outside a bar in southern California, and the attack was being investigated as a possible hate crime, police said.

The victim, a film student from San Dimas, blacked out from being beaten early Monday morning outside the popular Silver Fox bar in Long Beach, Calif., where he had gone with his boyfriend, CBSLA.com reported. He was hospitalized overnight and released with non-life threatening injuries, Long Beach Police Cmdr. Joe Stilinovich told NBC News on Wednesday afternoon.

The Marines were arrested for assault and charged with a hate crime, among other charges, though it will ultimately be up to the Los Angeles County District Attorney’s Office to determine what charges will be pursued, Stilinovich said. Names of the suspects won’t be released until charges are formally filed.

“We are out seeking additional witnesses at this time and conducting a thorough investigation to ensure that the appropriate charges are presented to the district attorney’s office,” he said, adding that authorities were trying to determine the role each suspect played in the assault. When asked what made the attack a potential hate crime, he said: “During the course of the assault and prior to the assault, statements were made by the suspect (and/or suspects), derogatory statements, regarding the victim’s sexual orientation.”

The Marines were out on bail and have returned to their units, a Marine Corps' spokesman told NBC News. They came into the bar late Sunday or early Monday. One of them allegedly made derogatory remarks to the man, according to media reports.

"You could tell by the tone of his voice that he [the Marine] was uncomfortable. He was making a demeaning remark," Silver Fox Manager John Barnes told the Press-Telegram on Tuesday, adding that the alleged attacker had called the victim “sweetheart.”

The victim, who told CBS that he did not want to be identified out of concern for his safety, said the assault occurred outside the bar. Witnesses said the men used homophobic slurs, the television station reported.

“He starts pushing me and calling me f–,” the victim said, noting that he later blacked out.

Two people who tried to help the victim were also attacked but either were not hurt or had only minor injuries, police spokeswoman Nancy Pratt said late Tuesday in a statement.

“Based on the preliminary investigation, it was determined that an assault had occurred to a male adult by several male suspects after they had left the establishment,” she said. “The Long Beach Police Department is handling this case and are investigating the incident as a possible hate crime.”

The Marine Corps learned of the attack on Tuesday and was performing its own inquiry as well as cooperating with police, Maj. Manuel Delarosa, a spokesman for the Marines, said early Wednesday.

The Marines, based at Camp Pendleton in southern California, were in their first enlistment, he said, adding that the attack was an isolated incident and that last year's repeal of the military's "don't ask, don't tell" policy hadn't come up as an issue.

"This is behavior that's not acceptable in the Marine Corps," Delarosa said. "Any crimes of intolerance are unacceptable and not tolerated as far as behavior expected of a United States Marine."

Stilinovich said the department tracked local hate crime incidents, which had reached a low of five last year in the past decade. Excluding Monday’s alleged attack, there have been two such incidents this year, he said.

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