WASHINGTON (AP) — Federal agents broke up a billion dollar Medicare scam, April 9, that peddled unneeded orthopedic braces to hundreds of thousands of seniors. Two dozen people were charged, including doctors accused of writing bogus prescriptions.

The Justice Department said the scheme relied on overseas call centers to pry Medicare numbers from beneficiaries. Authorities also announced charges against owners of call centers, telemedicine firms and medical equipment companies that shipped unneeded back, shoulder, wrist and knee braces.

Profits from the scheme were laundered through offshore shell companies and then used to buy high-end cars, yachts and luxury homes here and abroad, officials said.

Medicare’s anti-fraud unit said it’s taking action against 130 medical equipment companies implicated. The companies billed the program a total of $1.7 billion, but not all of it was paid out.

The loss to Medicare was estimated at more than $1.2 billion.

The Health and Human Services inspector general’s office said the fast-moving scam was fueled by kickbacks among the parties involved. The FBI, the IRS and 17 U.S. attorney’s offices took part in the crackdown.

Officials said it’s one of the biggest frauds the inspector general’s office has seen.