Kapoor, the founder and former chairman of Insys Therapeutics, was found guilty of racketeering conspiracy after 15 days of deliberations.

John Kapoor, the billionaire founder of Insys Therapeutics Inc., leaves the federal courthouse during the trial accusing Insys executives of a wide-ranging scheme to bribe doctors to prescribe an addictive opioid medication,

BOSTON — A wealthy drug company founder was convicted Thursday of directing a scheme to bribe doctors across the country to prescribe a highly addictive fentanyl spray.

John Kapoor, the founder and former chairman of Insys Therapeutics, was found guilty of racketeering conspiracy after 15 days of deliberations in a trial that put a spotlight on the federal government’s efforts to go after those it views as responsible for fueling the deadly opioid crisis.

Four other former employees of the Chandler, Arizona-based company were also convicted.

Kapoor and the others were accused of conspiring to pay doctors bribes and kickbacks in order to boost sales for Subsys, which is meant for cancer patients with severe pain. The bribes were paid in the form of fees for sham speaking events that were billed as educational opportunities for other doctors, prosecutors allege.

Prosecutors said Insys staffers also misled insurers about patients’ medical conditions and posed as doctors’ office employees in order to get payment approved for the costly drug.

Lawyers for Kapoor and the others argued in court documents that they couldn’t be convicted because prosecutors failed to prove that they intended for doctors to prescribe the drug to patients who had no medical need for it.

Kapoor’s attorney sought to shift the blame onto the company’s former vice president of sales, Alec Burlakoff, who pleaded guilty to the bribe scheme in November. Attorney Beth Wilkinson said Burlakoff was cutting side deals with doctors on his own and lied when he testified against Kapoor because he’s trying to save himself.

The charge calls for up to 20 years in prison, but as first-time offenders, Kapoor and the others would likely get only a fraction of that.

Prosecutors said Insys staffers also misled insurers about patients’ medical conditions and posed as doctors’ office employees in order to get payment approved for the costly drug.

Lawyers for Kapoor and the others argued in court documents that they couldn’t be convicted because prosecutors failed to prove that they intended for doctors to prescribe the drug to patients who had no medical need for it.

Kapoor’s attorney sought to shift the blame onto the company’s former vice president of sales, Alec Burlakoff, who pleaded guilty to the bribe scheme in November. Attorney Beth Wilkinson said Burlakoff was cutting side deals with doctors on his own and lied when he testified against Kapoor because he’s trying to save himself.

The charge calls for up to 20 years in prison, but as first-time offenders, Kapoor and the others would likely get only a fraction of that.