The racketeering, conspiracy and fraud charges against John Kapoor of Phoenix, Arizona, stem from his time at Insys. Six other former executives were charged and arrested in the same case late last year.
Just last month, the mother of a woman who died from using their former company's products told lawmakers, "The only thing that keeps us going at this point in our lives is that the people who did this to my baby will be held accountable for their actions."
According to authorities, the bribes and kickbacks took different forms, including food and entertainment, speaker fees and money for marketing events.
However, while bribes helped propel doctors to issue new prescription for the fentanyl spray, insurers "were reluctant to approve payment for the drug when it was prescribed for patients without cancer," so the company started misleading insurers and agents "into authorizing payment for the Fentanyl Spray," the indictment says.
Last month, Deborah Fuller told a Senate roundtable in Washington that "losing a child is agonizing, but then learning that [daughter] Sarah died from a drug that she should never have been prescribed has caused us so much more anguish and outrage."
"Learning of the massive fraud in which Insys was engaged to get people like Sarah to take Subsys really has made us question humanity," she added.
She said Insys called Sarah's health insurer "pretending to be calling from her doctor's office and the like, telling the insurance company that Sarah needed Subsys because she had cancer and was suffering from breakthrough cancer pain."
"That call was Insys' death wish for our daughter in exchange for profit," Fuller said, adding that the online pharmacy filling the prescription "would look the other way and deliver a carton of deadly fentanyl directly to Sarah's doorstep."
"I believe that Sarah's death certificate should be changed to indicate her death was a homicide and the cause of death should be changed to 'corporate greed,'" Fuller said.
After news of Kapoor's arrest today, McCaskill issued a statement, saying: "Evidence from our investigation suggests that Insys was engaged in systemic fraud and took actions that directly harmed their own customers and public health as a whole. This company has repeatedly gotten away with fines that amounted to a slap on the wrist for actions that helped fuel a nationwide epidemic that's claimed hundreds of thousands of American lives."
--ABC News' Tom Shine contributed to this report.