(CBS NEWSPATH) – It may seem like an odd crime in the digital age, but thieves are stealing people’s mail.

Dottie and Charlie Leighton recently wrote a $37 check for the power bill and dropped it in the same Boston area blue mailbox they’ve used for years. But days later the bank called and said someone was trying to cash that same check, now with an amount of $9,800. The Leightons told the bank not to cash it.

“They could empty a whole bank account out. We have quite a bit in the checking account and luckily, they stopped it,” Dottie Leighton said.

The crime is being seen nationwide, with thieves stealing checks from mailboxes outside of homes, at apartment buildings and from those blue boxes. Authorities say sometimes criminals use homemade devices to fish mail out of the box. In other cases, they use a stolen master key, known as an arrow key. Last year police near Chicago released video of a man opening a blue box with a key and taking out all of the mail.

David Maimon is a professor of criminology at Georgia State University and has been tracking criminal groups that wade through stolen mail to find checks.

“Once they have the arrow keys, they have access to hundreds of mailboxes simultaneously,” Maimon says.

Thieves use can use chemicals to remove writing on a check and then replace the name and amount. More sophisticated criminals can go a step further.

“Once you have the check, you essentially have the entire information you need in order to manufacture more and more checks,” Maimon says.

Authorities in several parts of the country are asking people to drop mail inside the post office instead of in a blue box. The Leightons’ new strategy is to circumvent the mail.

“We are going to pay as much as we can online,” Charlie Leighton says.

The couple plans to limit using paper checks, to prevent becoming victims again. Authorities say people should not leave checks in their home mailboxes. The Better Business Bureau advises people who write checks to buy a pen with enduring black ink, which is very difficult to wash off.