Chicago police on Sunday were asking for help in finding a man they said robbed someone at gunpoint on the Blue Line on Chicago's West Side.

Police said around 8 a.m. on Halloween Friday, Oct. 31, the man came up to another man on the platform for the Kedzie-Homan stop on the Chicago Transit Authority train line in the median of the Eisenhower Expressway. The man pulled out a gun and demanded the victim's property, police said.

Police described the robber as a Black male between the ages of 25 and 30, standing 5 feet 8 to 5 feet 11 inches tall and weighing 175 to 180 pounds. He had a beard, and was last seen wearing a black short-sleeved shirt with white stripes on the front of the shirt and sleeves, gray jeans with rips on the legs, and white gym shoes, police said.

Anyone with information was asked to call Chicago police Mass Transit Detectives at 312-745-4447, or submit an anonymous tip to CPDTIP.com and use reference #JJ-473214.