Two former drug salesmen were arrested last week for allegedly paying physicians to prescribe fentanyl, USA Today reports. Fentanyl has received heavy scrutiny after it was announced Prince died from an accidental overdose of the drug.

Fentanyl, a powerful opioid, can be up to 100 times more potent than morphine, the article notes.

The salesmen worked for Insys Therapeutics, which makes Subsys, a fast-acting form of fentanyl that is sprayed under the tongue. Subsys provides pain relief in as little as five minutes. In contrast, fentanyl patches provide a slow, continuous dose of painkiller.

According to the complaint, the salesmen paid two New York-area doctors $259,000 in kickbacks in 2014. Court documents say the doctors wrote more than $6 million worth of prescriptions for Subsys that year—more than all but a few physicians in the country. The complaint states that a manager for the company allegedly knew about the scheme, and told sales staff to demand that doctors prescribe large quantities of fentanyl in exchange for the payments.

The company said in a statement that it is against Insys policy to provide money or items of value to doctors in order to encourage them to write prescriptions.

Diego Rodriguez, an FBI assistant director who oversees the New York office, said in a statement that the alleged scheme is “one of the reasons we’re experiencing an epidemic of overdoses and deaths in this country.” He said that according to the charges, the doctors “saw a huge payday that potentially put people’s lives in danger.”

Court documents state that the salesmen made the payments appear legitimate by organizing fake educational seminars, at which the doctors were supposed to speak. The seminars were in fact mostly social events held at costly New York restaurants. The salesmen often took the doctors out for drinks at bars and strips clubs after dinner, according to the complaint.