Police said the crimes happened in August and September in the city's South Shore neighborhood.
In each incident, a Lyft or Uber driver picked up two male customers, and one asked to use the victim's cellphone to make a call, police said.
Then, both suspects fled from the vehicle on foot with the victim's phone.
During two of the incidents, one of the customers took out a gun and demanded the victim's phone.
The thefts and robberies have happened at the following times and locations:
- 6700-block of South Crandon Ave. on Aug. 30 at 12:03 a.m.
- 6800-block of South Crandon Ave. on Aug. 30 at 10:30 a.m.
- 6700-block of South Crandon Ave. on Sept. 6 between 2 a.m. and 2:15 a.m.
- 6900-block of South Crandon Ave. on Sept. 6 between 2 a.m. and 3:30 a.m.
- 6700-block of South Crandon Ave. on Sept. 6 at 4 a.m.
- 6700-block of South Crandon Ave. on Sept. 8 at 5:30 p.m.
- 6800-block of South Crandon Ave. on Sept. 9 at 6:18 a.m.
- 6700-block of South Crandon Ave. on Sept. 11 at 12:30 a.m.
Police said the suspects, described as between 12 and 20 years old, wear hooded sweatshirts.
Police asked anyone with information to contact them at 312-747-8384.
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