LAWRENCE (CBS) – A food stamp trafficking scam defrauded state and federal cash assistance programs out of $2.5 million, prosecutors say.

Authorities arrested six people after raiding four convenience stores in Lawrence Wednesday morning.

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Since June 2012, investigators have suspected that store owners and employees were “trafficking” food stamp benefits. The illegal practice involves businesses allowing people to pay a fee in order to get cash from their food benefits.

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“This is not a victimless crime,” Essex County District Attorney Jonathan W. Blodgett said in a statement. “We all pay the price when the greedy few defraud the taxpayers out of scarce public resources that are meant to feed, house and clothe our most needy residents.”

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William G. Squires, the special agent-in-charge at the U.S. Department of Agriculture Office of the Inspector General, said state and local law enforcement have been working together to protect the integrity of food stamp programs.

“The Supplemental Nutrition Assistance Program was created to provide food and nutrition to those who truly need this assistance,” he said. “Those who are involved in fraud and abuse of SNAP and other USDA programs will be aggressively pursued by our office.”

The stores involved in the scam were Gil’s/Noelia on Haverhill Street, Santiago Convenience on Lowell Street, El Leon Rojo on Hampshire Street and Bonao Market on Newbury Street, prosecutors said.

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Martin Santiago, 47, of Haverhill; Cristian Pena, 44, of Lawrence; Esperanza Ortiz, 47, of Lawrence; and Ramon Pena, 66, of Lawrence, face charges including trafficking in EBT benefits and money laundering. Two of Santiago’s clerks are also charged with conspiracy to commit larceny.