CHICAGO - Heirs of Prince have sued an Illinois hospital and pharmacy chain Walgreens, saying they could have prevented the singer's 2016 death if they had properly diagnosed and treated his overdose days earlier, a court document showed on Tuesday.

The wrongful death lawsuit, filed in Cook County Circuit Court in Chicago, accuses a doctor and pharmacist at Trinity Medical Center in Rock Island, Illinois, of failing to properly investigate the overdose or see that the pop star received appropriate counseling.

The six heirs also accuse two Walgreens pharmacists of improperly dispensing prescription medication to Prince, according to the lawsuit.

Prince, 57, was found dead at his Paisley Park home and recording studio complex near Minneapolis on April 21, 2016. The official cause of death was a self-administered overdose of the painkiller fentanyl, which is 50 times stronger than heroin.

A Minnesota prosecutor said last week he could not bring any criminal charges in connection with the "Purple Rain" singer's death after a two-year investigation failed to determine where he obtained a counterfeit painkiller laced with fentanyl. - Reuters