Seattle police are investigating after they say a plainclothes officer tried to break up a fight in a West Seattle alley Thursday night and opened fire on a man who pulled a gun.

Police do not believe anyone was struck by the gunfire, according to a statement from the department.

The 45-year-old officer was on duty in plainclothes in the 2300 block of California Avenue Southwest in the North Admiral neighborhood when he saw the fight around 10:30 p.m., according to police. The officer went to break up the fight, police said, when at least one of the men drew a handgun and pointed it at the officer, according to the police statement.

The officer was not wearing a body-worn camera, as he was working a plainclothes assignment, according to the statement.

The officer drew his gun and fired multiple times at the man, according to the statement. Police said the “group of assailants” ran away, but that a 29-year-old man with minor injuries from the assault remained at the scene and others were detained. No one had been arrested as of Friday afternoon, and detectives are still searching for other people who were involved.

Police said they found a handgun in a dumpster.

Police spokesman Patrick Michaud said Friday that he could not provide details on whether the officer was alone, called for backup or identified himself as an officer. Detectives are looking for surveillance footage from businesses in the area as they investigate the shooting.

The officer, who has worked for the department for five years, has been placed on administrative leave as the Force Investigations Team conducts a probe into the officer’s use of force.