Most of the heists have occurred between 11:30 p.m. and 2:15 a.m. at drug stores, convenience stores or restaurants.
The latest incident happened Sunday in the 1300 block of South Halsted Street, according to the alert.
The robber, who sometimes brings an item to the counter first before demanding money from a cashier at gunpoint, even held up three different establishments in the space of a half an hour in the early morning hours of Jan. 31.
The robber is described as an Hispanic man who is between the ages of 22 and 40. He stands 5-foot-5 to 5-foot-10 and weighs between 180 and 220 pounds. During the robberies, he wears a dark hooded sweatshirt and, sometimes, a black knit cap.
The following robberies are being investigated:
- 3600 block of North Western Avenue on Jan.18 at 11:30 p.m.
- 1500 block of West Fullerton Avenue on Jan. 27 at 10:45 a.m.
- 1700 block of North Clybourn Avenue on Jan. 29 at 11:58 p.m.
- 2800 block of North Ashland Avenue on Jan. 31 at 1:25 a.m.
- 1700 block of North Sheffield Avenue on Jan. 31 at 1:38 a.m.
- 100 block of West Division Street on Jan. 31 at 2 a.m.
- 2900 block of North Broadway on Feb. 03 at 2:15 a.m.
- 2200 block of North Lincoln Avenue on Feb. 06 at 2 a.m.
- 300 block of West Chicago Avenue on Feb. 06 at 3:15 a.m.
- 800 block of West Jackson Boulevard on Feb. 09 at 7:55 p.m.
- 1300 block of South Halsted Street on Feb. 10 at 1:40 p.m.