What is "check washing?" And how did a group of thieves take victims for more than $50,000?

MILWAUKEE (WITI) -- You've probably heard of money laundering -- but what about check washing? It could happen to you, if you're not careful! So how are thieves able to get ahold of your checks?!

Surveillance video shows thieves stealing from mailboxes of businesses. A savvy business owner had the cameras installed after reports of suspicious break-ins.

"He got a ping on his cell phone and he was able to zoom in and identify his business mailbox was being broken into," U.S. Postal Inspector Rachel Sileski said.

The video shows the car, and the image of Wilfredo Bermudez, the ring-leader 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," Sileski said.

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 themself and without question they could go in and cash it," Sileski said.

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, your checking and savings to make sure everything is reconciled and all the checks can be accounted for," Sileski said.

It is always a good idea to get your free yearly credit check.

The suspect in this case, Wilfredo Bermudez, was sentenced to four years in federal prison and ordered to pay back more than $50,000.

CLICK HERE to request a copy of your credit report.