TROUTDALE, Ore. -- A woman who signed up online to be a secret shopper said she became a victim of check fraud.

The woman, who spoke on camera but only wished to be identified as Sara, said she received a contract and a check for nearly $4,000 in the mail after signing up on the Internet.

She was told to use $70 to $100 to buy items during secret shopping trips and then send the remaining cash back to the research company through Money Gram.

"It says it comes from a Consumer Research Institute; it has a business ID," Sara said of the contract. "They give me a rep ID number."

The researchers told her they were also testing the quality of the money wiring service.

Sara said she brought her first out-of-state check to U.S. Bank in Troutdale and received cash on the spot. She received another check in the mail and cashed it the next day.

A few days later, however, Sara said the bank told her they were closing her accounts and she owed them $5,500 because the checks were fake.

"It's like, 'Oh my God,' that's our savings," Sara said. "It's all we have."

Sara said she wanted to warn others not to fall for the secret shopper scam. She also blamed the bank for not holding the out-of-state checks so they could check them out. She said the bank failed to protect her.

"I think it could've been stopped at the bank," she said.

Phone calls to U.S. Bank were not returned by FOX 12's Tuesday night deadline.

Woman Says She Lost Thousands In Secret Shopper Scam