The former owner of a South Georgia peanut butter plant and three other ex-employees are facing federal charges in connection with a salmonella outbreak four years ago that sickened hundreds of people and was linked to nine deaths.

The 76-count indictment charges Stewart Parnell, the former owner of Peanut Corp. of America, with fraud, conspiracy, obstruction of justice and other offenses linked to contaminated food from an outbreak of salmonella linked to his Blakely, Ga. plant.

Also named in the indictment are Michael Parnell, Stewart’s brother and a company vice president; Samuel Lightsey, a plant manager; and Mary Wilkerson, a quality assurance manager.

The charges come four years after federal investigators linked the deadly national outbreak to Parnell’s southwest Georgia plant. Inspectors who probed the site found roaches, mold and a leaky roof, and the company filed for bankruptcy soon after its tainted products were recalled.

After the probe started, Congress released emails from Parnell that depicted him as encouraging his employees to ship out peanut products even after reports that salmonella was detected. “Turn them loose,” he wrote in one email released by investigators at the time.

Stewart Parnell has remained tightlipped throughout the probe. He repeatedly invoked his right not to incriminate himself in 2009 when summoned to testify by a congressional subpoena. His attorney could not be reached for comment on Thursday.

Prosecutions in tainted food cases are fairly rare, and they generally lead to fines against companies rather than jail time or other punishments for individuals. Moore, though, said the four defendants could face decades in prison. But U.S. Attorney Michael Moore said the “complex and extensive” nature of the investigation didn’t yield quick results.

“Unfortunately and as alleged in the indictment, these defendants cared less about the quality of the food they were providing to the American people and more about the quantity of money they were gathering while disregarding food safety,” he said.

Food safety watchdogs said they were encouraged by the federal indictments.

“I think for the FDA to be credible, they had to do something like this and send a message to the food industry that this is not an acceptable practice,” said Mike Doyle, a University of Georgia food safety scientist.