BOSTON — A federal jury on Thursday found the top executives of Insys Therapeutics, a company that sold a fentanyl-based painkiller, guilty of racketeering charges in a rare criminal prosecution that blamed corporate officials for contributing to the nation’s opioid epidemic.

The jury, after deliberating for 15 days, issued guilty verdicts against the company’s founder, the onetime billionaire John Kapoor, and four former executives, finding they had conspired to fuel sales of its highly potent drug, Subsys, by not only bribing doctors to prescribe their product but also by misleading insurers about patients’ need for the drug.

The verdict against Insys executives is a sign of the accelerating effort to hold pharmaceutical and drug distribution companies and their executives and owners accountable in ways commensurate with the devastation wrought by the prescription opioid crisis. More than 200,000 people have overdosed on such drugs in the past two decades.

Federal authorities last month for the first time filed felony drug trafficking charges against a major pharmaceutical distributor, Rochester Drug Cooperative, and two former executives, accusing them of shipping tens of millions of oxycodone pills and fentanyl products to pharmacies that were distributing drugs illegally.