John Kapoor, the founder of US drug maker Insys, was sentenced to five and a half years in prison on Thursday for helping fuel America's deadly opioid crisis. The 76-year-old became the first owner of a pharmaceutical company to go to prison over the crisis that has killed tens of thousands of Americans.

Kapoor was convicted in May of an elaborate scheme that saw Insys pay doctors money to prescribe the company's addictive painkiller Subsys to patients who didn't need it.

He was found guilty of criminal conspiracy, along with four other former executives of the Arizona-based firm, following a 10-week trial in Boston. In 2017, President Donald Trump declared the opioid crisis a national public health emergency.