In each incident, four men approached a child or teen walking alone and implied they had a gun or showed a gun, according to Chicago police.
The men then demanded their belongings and fled the scene, police said.
The robberies happened:
- About 8:15 p.m. March 18 in the 6100 block of West Newport Avenue;
- About 5:20 p.m. March 19 in the 4000 block of North Major Avenue; and
- About 8:25 p.m March 29 in the 3500 block of North Neenah Avenue.
The four men are believed to be between 17 and 25 years old, 5-foot-7 to 6-foot, and between 130 and 160 pounds with slim builds, according to police. Two men have medium-length braids, police said.
Anyone with information is asked to call Area Five detectives at 312-746-7394.