The U.S. Marshals service has seized 21 luxury and performance cars from owners of an Alabama pill mill. And now, those cars -- and jewelry -- are being auctioned off in Austin.

John Patrick Couch and Xiulu Ruan were convicted in March of numerous charges. Ruan was sentenced to 21 years in prison and ordered to pay more than $10 million in restitution. Couch was sentenced to 20 years and ordered to pay $14 million.

Their cars are now up for auction at the Hilton Austin Airport hotel. They include an Aston Martin convertible, Bentleys, Lamborghinis, Porsches, Ferraris, a Shelby Series 1 convertible, and a Saleen S7.

Jewelry is also being auctioned inside the Bergstrom Ballroom.

Registered bidders can preview what's for sale until 7 p.m. Friday night and until Saturday from 8:30 a.m. to 10 a.m.

Online pre-bidding already has begun. The items can be viewed online here.