An off-duty Beverly Hills police officer shot and Thomas Caldwellkilled an armed person engaged in a brawl on the street in southern California on Wednesday night, authorities say.

Officers responded to reports of a shooting in an area right off Interstate 405 in North Hills, a neighborhood about 20 miles northwest of downtown Los Angeles, just after 8 p.m.

When officers arrived on scene, they were met by the off-duty cop, who called in the shooting, according to a news release from the Los Angeles Police Department.

The off-duty officer and a buddy were driving down Roscoe Boulevard when they saw two men fighting, one was armed with a pipe and the other with a gun, according to LAPD.

The off-duty Beverly Hills officer got out of his car to intervene, shooting the man armed with the gun. The other man, armed with the pipe, ran from the area, LAPD said.

"The off-duty officer remained at scene and is cooperating with officers," LAPD said.

Investigation underway, LAPD says

Authorities were able to apprehend the man armed with the pipe later that night, reporting that the man armed with the gun died at the scene. LAPD has not revealed the identities of the men, including the off-duty police officer, who were involved in the shooting.

LAPD was called in to assist with the investigation, with department detectives actively "investigating this shooting."

Brian Wendling, LAPD Captain, told KTLA5 that they did not "not have all the facts" but confirmed that an officer-involved shooting had taken place. The circumstances surrounding the fighting and shooting were not immediately known.

Wendling also told KTLA5 that they would prefer off-duty officers to be "good witnesses" but do have a "duty to stop" if someone's life is in danger.