CHICAGO (CBS) -- The U.S. Postal Service is offering up to $50,000 for information on a person suspected of robbing a postal worker in Chicago's West Lawn neighborhood. 

According to the USPS's Inspection Service, the armed robbery happened on Wednesday, October 19 around 5:15 p.m. in the 5900 block of South Kolin Avenue in West Lawn.

The suspect flashed a gun and demanded what the carrier had with them. The suspect wore a black facemask, black jacket, dark pants and rode off on a bicycle. 

The USPS said the suspect is considered armed and dangerous. 

Anyone with information is asked to contact the: U.S. Postal Inspection Service at 1-877-876-2455 (say "Law Enforcement") and use Reference Case No. 3866869.