Chicago police have issued a warning to residents about a series of robberies on the same block in East Chatham.

Police say there have been four separate robberies in the past month in the 900 block of East 81st Street.

The suspects, a group of males in their late teens and early twenties, lure victims by responding to online ads about meeting up and selling items.

Police say to meet with prospective buyers in a public place and write down serial numbers of any items you bring with you.