Chicago police on Tuesday issued an alert after armed robbers targeted three victims using an online marketplace in South Deering.

The robberies happened in the afternoon and evening hours on Sept. 6, Oct. 12, and the latest on Tuesday, all in the 10500 block of South Oglesby Avenue in Trumbull Park.

Police said in each incident, one to three suspects used an online marketplace to set up meetups to buy items such as clothing and mobile devices.

While meeting up with the victims, the suspects approached and announced a robbery before taking the victims' belongings. In one of the robberies, a handgun was shown. 

Police were not able to give a detailed description of the suspects, but said they wore all black clothing and masks.

Anyone with information about either robbery is asked to contact Area 2 detectives at 312-747-8273 or submit an anonymous tip at CPDTIP.com, using reference number P2502030.