A Suffolk County business owner said he became the latest victim of fraud when he mailed checks at the Bay Shore Post Office last month.

Rocket Express co-owner Rich Miller said he routinely mails business checks at the postal facility early in the morning before it opens.

"I write checks, I stamp them and stick them in the mailboxes and right outside the post office, I would think that it's safe," Miller said.

But that would quickly turn out to be untrue.

Miller's bank flagged four checks that he mailed between Aug. 18 through Aug. 21 for potential fraud, but not before an alleged thief fished the mailbox outside the facility, whitewashed two checks and cashed them under the name "Derrick Johnson."

It's unclear if the suspect used his real name or an alias, but Suffolk County Police confirm the department is investigating.

"You pay your bills online, there's fraud. You write out checks and you put them in the mail, there's fraud," Miller said.

The scheme cost Miller's small trucking company $2,600.

One of the stolen checks was for utilities and the other was for health insurance.

A federal report from earlier this year found that check fraud is on the rise and a significant amount of that is done through mailboxes that sit outside postal facilities.

"Fraudsters take advantage of regulations requiring financial institutions to make check funds available within specified timeframes, which is often too short a window for the consumer or financial institutions to identify and stop the fraud," part of the warning reads. "As a result, the compromised checks clear, and the funds are withdrawn by the criminal participants before the fraud is detected."

Miller said he's still fighting to get his money back, but also hopes his situation serves as a warning to others to think twice before they mail confidential, sensitive, or important letters.

"My recommendation is, bring your mail into the post office, don't use the outside boxes and hope for the best," he said.