Randy Constant, 61, was found dead in a vehicle in the garage of his Chillicothe, Mo., home Monday evening, police said.
Investigators had held a news conference in Iowa hours earlier announcing Constant’s prison sentence.
The Livingston County coroner said Constant died from carbon monoxide poisoning. The finding was confirmed by a post-mortem examination at the University of Missouri Medical Center, he said.
Prosecutors said Constant falsely marketed non-organic corn and soybeans as certified organic on a massive scale. His sales amounted to 7 percent of organic corn grown in the U.S. in 2016 and 8 percent of the organic soybeans.
Constant also owned an Iowa-based brokerage, which sold his grain as feed for chickens and cattle. Those animals were then marketed for their meat and meat products that were advertised as organic.
U.S. District Judge C.J. Williams said Constant did “extreme and incalculable damage” to consumers who were fooled into paying extra to buy supposedly “organic” products like eggs and steak. Instead, they purchased food that relied on farming practices like the use of chemical pesticides to grow crops, he said.
A federal judge sentenced Constant at a hearing on Friday for leading what prosecutors dubbed the “Field of Schemes fraud.”
“We are still in shock and disbelief over yesterday’s events, when my husband took his own life,” Constant’s wife, Pam, said in a statement. “I know Randy was deeply ashamed of his conduct. As much as we tried to be there for him ... it was clearly just too much for Randy.”
She said he would be remembered as “a wonderful father, community leader, tireless volunteer and my beloved husband of 39 years.”
Constant had been free on bond since pleading guilty to wire fraud last December and had cooperated with investigators since 2017.
Constant's lawyer, Mark Weinhardt, described his client last week as a “pillar of the community” who had served on the school board and donated his time and money to local causes and the Methodist church. He said he was stunned by the contradiction between Constant’s record of good deeds and his lengthy fraud sheet.
Constant’s death came as prosecutors publicized his prison term, which they said would deter other farmers from defrauding the National Organic Program.
“Randy Constant and his co-conspirators lied to the American public and cheated thousands of consumers,” U.S. Attorney Peter E. Deegan Jr. said. “For years, Constant put personal greed and self-interest above all else.”
The Associated Press contributed to this report.