LANCASTER, Ohio (WCMH) — Law enforcement agencies across central Ohio are warning people to take steps to protect their bank accounts after a string of mail thefts across the area.

Justin Edwards is one of roughly 45 people who filed a report with the Fairfield County Sheriff’s Office after thousands of dollars were drained from his checking account because of the thefts.

“I got an email saying that my checking account was zero,” Edwards said. “At first, it was panic.”

Edwards looked at his bank account online.

“There were two checks written. One for like $8,000. The other one was for $2,000,” Edwards said.

His address, account number and routing number were printed on both checks, even though he didn’t write them. But he had recently mailed three checks, for bills, using a blue U.S. Postal Service mailbox near the Kroger on Refugee Road in Pickerington.

The address for that mailbox appeared several times in reports provided by Fairfield County Sheriff Alex Lape.

Lape said thieves are removing pen ink from checks that are stolen from mailboxes, then changing the recipient and amount. It’s a process known as “check washing.” The sheriff said it’s become a rapidly growing concern in his jurisdiction and others in the area.

Surveillance video provided by Whitehall Police shows a group of assailants mugging a mail carrier and driving away with their keys and mail.

“This is happening in the whole central Ohio,” Lape said.

Lape expressed particular concern for those who prefer to avoid online banking and bill pay.

“You feel much more at ease and much more secure knowing that you can trust on the United States Postal Service to get your payment where it needs to go,” Lape said. “And that’s where we’re at the critical mass point, where the system is being taken advantage of and compromised.”

Edwards and his wife were able to resolve the issue with their bank, which said it is investigating the fraud and will return the stolen money. In the meantime, Edwards plans to pay bills online and “bite the bullet” on processing fees that typically come with that convenience.

Lape said his office regularly communicates with the U.S. Postal Inspector Service, which did not respond to requests for comment from NBC4.

“To get it under control would be great,” Lape said. “To bring some people to justice would be even better. And that’s the goal.”

NBC4 reached out to Columbus-based Huntington Bank for advice on how to protect your bank account. They recommend using indelible black ink on paper checks, following up with recipients to make sure they got the check, and making sure there’s no blank space in the ‘pay to the order of’ or ‘amount’ lines of checks. Huntington also recommends online banking and bill pay.

“Part of this issue also is, like myself, some folks aren’t comfortable doing their banking online — paying their bills online — because they’re afraid they’re going to have their accounts compromised through that process,” Lape said, suggesting that people mail checks by dropping them off inside the post office, instead of in an outdoor mailbox.