CHICAGO (CBS) -- Chicago Police say they're investigating three armed robberies of mail carriers. They all happened within a few blocks of each other in the city's South Shore neighborhood on March 17, 29, and 30. 

The incidents happened at the following locations and times: 

• 8000 block of South Kingston on March 17, 2024
• 7900 block of South Jeffery Blvd on March 29, 2024
• 7900 block of South Kingston on March 30, 2024

Police say in all three incidents, the on-duty postal worker was approached by a person armed with a handgun who then robbed them. 

No one was hurt. 

Anyone with information is asked to contact the Area 2 Bureau of Detectives at (312)747-8273.