The Wellesley Police Department, which has been getting more mail theft-related check fraud reports, is advising residents to take their mail directly into the post office to send it on its way.

Crooks have advanced from “fishing” schemes that involved using wires and sticky mouse traps to snag letters through mailbox slots to outright stealing postal carrier keys to open those big blue mailboxes and then overwriting people’s checks and cashing them. Wellesley and other communities replaced or retrofitted mailboxes a few years back to address fishing—while that served as a deterrent, criminals have found an even more efficient way to grab checks from mailboxes.

While heading to the post office to mail your stuff may be inconvenient and fly in the face of local efforts to cut down on traffic, the message also comes at the busiest time of year at the post office.

The theft of mailbox keys and subsequent check washing has become a national issue, with arrests for such crimes reported from Chicago to Maryland. A Chicago mail carrier recently reported being robbed at gunpoint for his key.

Not only are checks being altered and cashed, but personal information is being stolen from them and abused. The Wellesley police logs are filled with online fraud reports.

The Wellesley Police Department is advising residents not only to avoid official U.S. Postal Service mailboxes, but their own residential mailboxes as well.

“We want to be sure the residents are aware that these types of thefts are occurring in towns all across the state and that investigations into these thefts have revealed that the thieves have keys to the blue mailboxes. If you need to mail a check please do not use the blue mailboxes and do not leave it out for your postal carrier. All mail should be brought directly to the post office,” Wellesley Police Lt. Marie Cleary said to us in a follow-up email.