You may be familiar with the telemarketer scam calls that asked about a much-needed brace for seniors with pain. The Department of Justice announced Tuesday federal law enforcement officials have filed charges against 24 people in the U.S. who they said perpetuated the scam.

Those charged include doctors who the feds said wrote fake prescriptions for braces used on the back, shoulder, wrist or knees that were not needed, CBS News reported.

Call center owners, telemedicine firms and medical equipment company officials were also charged, The Associated Press reported.

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Telemarketers would call senior citizens to offer what they claimed were free orthopedic braces. If a person was interested, then the call would be sent to a location in either the Philippines or in Latin America, CBS News reported.

Then the call would be sent to a telemedicine company for a doctor consult after Medicare coverage was verified.

The doctors then would write a prescription for a brace, or several braces, whether one was needed or not.

The call centers would collect the prescriptions and send to a medical equipment company which would send the brace to the victims. The "free" brace would then be billed to Medicare with it paying $500 to $900 per brace to the equipment company, and the company then would kick back $300 per brace, according to CBS News.

The money then went to buy expensive cars, yachts and luxury homes, the AP reported.

The investigation started last year after the Medicare fraud hotline started getting calls from upset beneficiaries.

The defendants were across the country, located in California, Florida, New Jersey, Pennsylvania, South Carolina and Texas.

Federal officials said it was one of the biggest fraud rings they've seen, according to the AP.