VANCOUVER, Wash. -- A Vancouver woman warned others Tuesday about a check washing scheme in which she became a victim.

Marianne Hertsche said she wrote a $50 check payable to her credit card late last month and placed it in her mailbox. She discovered the check was stolen when she tried to balance her checkbook two weeks later.

"I was really shocked. I mean, I was sitting at my desk and all of a sudden I went, 'Wait a second. That's not what I wrote on the check,'" Hertsche said.

According to bank records, someone cashed Hertsche's check two days after she wrote it. The check was cashed for $150 at an iQ Credit Union branch.

Clark County deputies believe a thief stole the check from Hertsche's mailbox and washed it down to remove the information. The thief then re-wrote the amount and forged Hertsche's signature.

"I was completely astonished that somebody would go ahead (and) go to these lengths and do this," Hertsche said.

Hertsche does not blame her credit union for cashing the check. In fact, she said the credit union reimbursed the money the thief took from her account.

Deputies said they're following leads in the case and have obtained a thumbprint given by the thief when the check was cashed.

A statement from the credit union said it encourages people to balance their accounts and monitor their statements to make sure nothing is out of the ordinary.

"Each situation is unique and we will work with customers to resolve them," said Jim Morrell, an iQ Credit Union spokesman.

In the meantime, Hertsche said she hopes others hear her warning.

"It must be a pretty good operation for them to be able to get it passed through people that deal with these checks every single day," she said.

Warning Issued Over Check Washing Scheme