PORTLAND, Ore. -

The crime is called "check washing," and in this case cost victims thousands of dollars. But one savvy business owner helped stop the act when he had surveillance cameras installed after reports of suspicious break-ins.  Sure enough, video caught thieves stealing from business mailboxes.

"He got a ping on his cellphone and he was able to zoom in and identify his business mailbox was being broken into," explained US Postal Inspector Rachel Sileski.

The video shows the car and image of Wilfredo Bermudez, who inspectors say is the ringleader of a scam that cost victims more than $50,000.

"He was obtaining business checks, he would wash and alter them and make them payable to himself and deposit them or cash them at the banks they were drawn on," said Sileski.

"Check washing" is the process of erasing details from checks to allow them to be rewritten.

"The checks that they obtained could be anywhere from $200 to $8,000. There was a large range of checks they negotiated," Sileski said.

In fact, they were often able to retrieve cash immediately and quickly by going to the bank where the check was drawn.

"So they could use their true identification and the check would be made payable to themselves and without question they could go in and cash it," explained Sileski.

Bermudez was sentenced to 4 years in federal prison and ordered to pay more than $50,000 in restitution to his victims.

Meantime, postal inspectors say this is yet another lesson on how important it is for all consumers to protect their identity.

"Be very diligent about checking your bank accounts, credit card statements for fraudulent transactions," said Sileski. "Your checking and savings to make sure everything is reconciled and all the checks can be accounted for."

Postal inspectors also recommend requesting a free yearly credit check. Everyone is entitled to  one free check every year with each of the three credit reporting agencies. The Better Business Bureau of Northeast Florida  recommends the website AnnualCreditReport.com.  It has step-by-step instructions and links to all three credit bureaus.