WESTERVILLE, Ohio (WCMH) — The Westerville Division of Police has warned residents to stop sending checks through the mail due to dozens of “check washing” cases being reported.

After stealing checks from the mail, criminals use chemicals to remove ink, then change the amount the check was written for and who it’s made out to. Det. Lt. Justin Alloway said most of WPD’s cases involve elderly victims who were just trying to pay bills.

“Unfortunately I believe this is a crime that is targeting our elderly populations,” Alloway said. “These criminals just prey on people that don’t know any better. They’re just going about their lives like they normally have and they’re taking advantage of the way they pay their bills.

More than 50 cases have been reported to the division since March.

“We’re talking about large sums of money here,” Alloway said. “Just trying to pay their bills that are $50, $100, $200 dollars, and all of the sudden they’ve got eight, nine, 10,000 dollars stolen from their bank account. It’s devastating for them.”

Investigators said most of the cases have happened after checks were dropped off at the outdoor boxes at post offices in town. They also said thefts from home mailboxes or indoor mailboxes at post offices cannot be ruled out.

“I would ask that no one would mail any type of check whatsoever. They should be hand delivered or set up electronic payments if you’re comfortable with who you’re paying. It is not safe to mail checks at this point,” Alloway said. “Once it is received into the postal service we don’t know where it’s stolen from there. Whether it’s from the mailbox, from a distribution center or at the delivery site.”

Dr. David Maimon, Director of The Evidence Based Cyber Security Research Group at George State University, and his team have been looking into the issue of stolen checks being sold on the dark web for more than two years.

“Once you have someone’s check you have so much information at your disposal that you can engage in different types of fraud and unfortunately we’re discovering this over and over again,” Maimon said.

Out of all Ohio cities in August, Westerville had the third most checks end up on the dark web after Columbus and Cincinnati, according to Maimon.

“I strongly support the recommendation. I think folks should do their best to refrain from sending checks or any other personal identifiers over USPS mail,” he said.