John Kelly O'Leary, 21, was arrested Monday by police in Evergreen Park, Ill., Deputy District Attorney Gretchen Ford of the hate crimes unit said in a statement. O'Leary was [dishonorably] discharged from the Marines on Oct. 19, about six weeks after the attack, Marine Corps’ spokesman Master Gunnery Sgt. Mark Oliva told NBC News. He will be extradited from Illinois to California to face the charges.

O'Leary and a group of friends, including other Marines, went to the Silver Fox bar in Long Beach, Calif. in the early morning hours of Sept. 3, 2012. O'Leary was accused of shouting anti-gay slurs outside the bar at closing time, which triggered the hate crime charge, said Jane Robison, a spokeswoman for the district attorney's office.

O'Leary has been charged with two felonies – battery with serious bodily injury and assault by means likely to produce great bodily injury – and faces up to eight years in prison, which includes time for the hate crime allegation.