CHICAGO (CBS) — A man tried to rob an on-duty plainclothes Chicago Police officer at gunpoint on the Near South Side Wednesday evening, police said.

Just before 6:30 p.m., the on-duty officer was seated inside a non-Chicago Police vehicle outside of a scheduled CAPS community policing meeting in the 2900 block of South Vernon Avenue, police said.

Two offenders came up in a black pickup truck, and the passenger in the pickup truck got out, took out a gun, and announced a robbery, police said.

The offenders just left upon realizing that the victim was a police officer, police said. The officer was in civilian dress.

Area Central detectives were investigating Wednesday night.