CHICAGO — Four attacks have been reported between Oct. 22 and Nov. 2 on the CTA Blue Line, prompting Chicago police to issue an alert to West Side residents.

According to police, three of the incident occurred at 720 S. Cicero from 3 to 7 p.m., with a fourth at 520 S. Cicero about 20 minutes later.

In all incidents, police say the suspect approaches the victim, displays a weapon and demands property.

In one instance, the suspect forcibly removes a victim’s cell phone. In another incident, the suspect threatens to shoot the victim before running off.

Police did not provide an image of the suspect.

Anyone with information should call (312) 746-8253 or submit an anonymous tip at cpdtip.com.