Four companies in western Washington are accused of defrauding thousands of dollars from consumers, including seniors, through tech support scams.

Charges were filed this week in the Western district of Washington against four defendants accused of defrauding consumers of thousands of dollars.

The cases, which targeted or primarily impacted seniors, are part of the largest-ever nationwide elder fraud sweep, according to the U.S. Attorney’s Office.

“We are stopping a key cog in the wheel of tech support fraud,” U.S. Attorney Brian T. Moran said in a statement. “By taking out those who process the payments for the fraudsters, we stop the flow of ill-gotten gain to those preying on our senior citizens.”

Businesses in Seattle, Shoreline, and Gold Bar are accused of collecting fraud payments, keeping a percentage of the money, and forwarding the rest to telemarketing centers in India. A fourth company was one of the fraudulent tech support companies that used those telemarketing centers.

The Shoreline company allegedly sent over $320,000 to India between December 2017 and May 2018, according to the U.S. Attorney’s Office.

The businesses are accused of using tactics such as telemarketers posing as technicians who would convince seniors to purchase expensive security software by claiming their computer had been taken over by a virus.

In some cases the telemarketers would allegedly offer refunds only to move money around within customers’ bank accounts and then ask for additional money to reimburse an “over-refund.”