(WTTW News)

The Chicago Police Department has issued a community alert following several reports of checks stolen from U.S. postal boxes.

Nearly a half-dozen such incidents were tallied in October, with thefts occurring across the city, from Garfield Ridge to Rogers Park.

Unknown suspects are using postal keys to open mailboxes, typically at night or on weekends, and removing mail. They're then either "washing" the checks — erasing the ink and writing in a new payee — or manufacturing a new check with routing and account numbers from the stolen checks, according to police. The amount of the check is then altered as well.

Police warned people to steer clear of using standalone mailboxes when sending checks, particularly after pick-up time, overnight or on weekends. Preferably checks should be mailed directly from a post office, and should be written using a fraud-prevention gel pen.

Victims of stolen, forged or altered checks should contact postal inspectors at 877-876-2455. Anyone with information about the recent thefts should call detectives at 312-746-8253.

Contact Patty Wetli: @pattywetli | (773) 509-5623 |  [email protected]