Chicago (CBS) — Chicago police are alerting CTA riders about a series of cell phone robberies on the Green Line over the past few weeks.

According to police, seven thefts and robberies have happened in or near the Pulaski, Central Park, and Kedzie stations since January.

Police say the offender or offenders wait until the train stops at a station, then take the victim’s cell phone and flee the station.

The incidents occurred at the following stations:

  • 200 block of North Kedzie on Jan. 25 at 9:45 p.m.
  • 3600 block of West Lake on Jan. 25 at 12:55 a.m.
  • 200 block of North Pulaski on Jan. 28 at 4:45 p.m.
  • 3600 block of West Lake on Jan. 29 at 7:45 a.m.
  • 4000 block of West Lake on Jan. 31 at 1:30 p.m.
  • 4000 block of West Lake on Feb. 5 at 6:25 p.m.
  • 3600 block of West Lake on Feb. 6 at 11:45 p.m.

Anyone with information is asked to contact Area North Detectives at 312-744-8263.