Victims, most of them elderly, paid $4,000 to $13,000 for handheld light-emitting devices called QLasers after being told that they could use them to treat more than 200 medical conditions, including cancer, cardiac arrest, HIV, diabetes, and Lou Gehrig’s disease, according to the Justice Department.

Now three people alleged to have sold the devices through multiple companies for more than a decade have been arrested on charges related to their involvement in a scheme and for violating a judicial order that previously was imposed after the alleged scheme was originally uncovered.

“As the indictment alleges, these individuals targeted vulnerable citizens for years, preying on weaknesses brought about by chronic illnesses and fear of death — all to enrich themselves, and even where the scheme entailed violating a direct court order to stop,” Acting Assistant Attorney General Chad A. Readler of the Justice Department’s Civil Division said in a statement. “This prosecution further demonstrates the department’s ongoing commitment to protecting older Americans from fraud and abuse.”

This past weekend, the department announced Tuesday, U.S. Postal Inspectors arrested Rapid City, SD, residents Robert “Larry” Lytle, 81, and Fredretta L. Eason, 76, as well as a resident of Canada, Irina Kossovskaia, 62. Lytle and Kossovskaia are charged with mail fraud, wire fraud, conspiracy, contempt and obstruction of government proceedings. Eason is charged with criminal contempt.

A fourth person, Ronald D. Weir, 38, also of Rapid City, agreed to plead guilty on Monday to  one count of conspiracy to introduce misbranded medical devices into interstate commerce with the intent to defraud and mislead.

The charges announced Tuesday follow a separate civil enforcement action brought by the United States against Lytle and his QLaser businesses in late 2014.

The use of the device to treat serious medical conditions is not supported by published clinical studies and it is not approved by the U.S. Food and Drug Administration, the Justice Department said. In 2015, during the civil case against Lytle, the federal court concluded that the product’s labeling was not only false and misleading, but also that using the device could be dangerous when used as Lytle directed. As a result, the court ordered Lytle and anyone working with him to stop distributing the devices.

The criminal contempt charges stem from the defendants’ disobedience of the court’s orders. In addition to criminal contempt, mail fraud and wire fraud, the grand jury also charged Lytle with obstruction of the FDA by making false statements and providing false documents during the agency’s inspections of his QLaser business.

In addition to fines, each count of mail and wire fraud in the indictment carries a maximum sentence of 20 years of imprisonment. Each of the conspiracy and obstruction counts carries a maximum sentence of five years of imprisonment. There is no statutory maximum penalty for criminal contempt.