In each incident, the robbers implied they had weapons, according to CPD.
All three of the robberies happened in the Loop. Two were on the same block of Michigan Avenue.
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Two happened at 7 and 7:30 p.m. Saturday in the 0- to 100-block of South Michigan Avenue, and one happened at 6 p.m. Sunday in the 200-block of East Randolph Street, police said.
The suspects are described as male and female and 15 to 25 years old.
Anyone with information is asked to call Area Three detectives at 312-744-8263.