PORTLAND, Ore. (AP) – Authorities in the Portland area have arrested 31 people accused of food stamp fraud.

Beaverton police spokesman Mike Rowe said Friday the investigation began when a detective learned the owner of Metzger Mart in Beaverton was exchanging Supplemental Nutrition Assistance Program benefits for cash.

Customers would use their SNAP card for a large purchase and then exit the store with something like a can of soda. Rowe says the owner was giving customers 50 cents on the dollar in cash.

Detectives later connected 30 others to the fraud. All have been accused of unlawfully using supplemental nutrition assistance, and the market owner faces other charges.

Rowe says more arrests are expected.

Law enforcement agencies throughout the metro area participated in the investigation.