PETALUMA, Calif. – A federal grand jury indicted four people on charges of conspiracy to distribute adulterated, misbranded and uninspected meat and mail fraud for their roles in the Rancho Feeding Corporation meat scandal.

Named in the indictment were co-owner Jesse Amaral Jr., Felix Sandoval Cabrera and Eugene Corda. Co-owner Robert Singleton was charged with one count of distribution of adulterated, misbranded and uninspected meat. The Petaluma, Calif.-based beef processor recalled more than 8.7 million lbs. of meat products that were processed from cows that had eye cancer. The charges carry prison terms and fines that vary from three to 20 years in prison with fines of $10,000 to $250,000.

The indictment alleges that from mid- to late 2012 through Jan. 10, 2014, Amaral directed Cabrera to process cattle that already had been condemned by a US Department of Agriculture veterinarian. Cabrera and other Rancho Feeding employees would then carve the "USDA Condemned" stamps out of the carcasses and process them for sale and distribution.

The indictment also alleges that Corda swapped uninspected cows with eye cancer for cattle that already had passed ante mortem inspection and were awaiting slaughter. The swaps happened during the inspectors' lunch breaks, during which plant operations were supposed to cease.

"Between January 2013 and January 2014, Rancho processed and distributed for human consumption carcasses, carcass parts and meat from approximately 101 condemned cattle and approximately 79 cancer eye cows," according to the indictment.

Amaral also is accused of mailing fraudulent invoices to farmers and charging the farmers handling fees for carcass disposal instead of paying them based on the sale price.

In May, Marin Sun Farms, a specialty meat purveyor in Point Reyes Station, Calif., successfully acquired Rancho Feeding's slaughterhouse.