CHICAGO (CBS)–Red Line riders are getting punched while waiting on the CTA platform at some stations, Chicago police said in a community alert.

During two incidents of random violence last week, multiple men were seen opening the side operator window of an L train and hitting people standing on the platform, according to Chicago police.

(Chicago Police)

Police hope these photos will help find the people responsible.

(Chicago Police)

The incidents happened around 7:45 p.m. Thursday, Feb. 22 at the Sheridan station and at 4:45 p.m. Friday, Feb. 21 at the State and Grand stop, according to police.