Members of Prince’s family have filed a lawsuit against an Illinois hospital and the Walgreens pharmacy chain, contending both could have done more to prevent the legendary entertainer’s opioid overdose death in April 2016, according to news reports.

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The suit follows a decision made last week by the Carver County Attorney Mark Metz against filing charges in the superstar singer's death. Following a two-year investigation, Metz, of Carver County, Minnesota, announced Thursday that "Prince died from taking a counterfeit Vicodin pill that contained fentanyl, a dangerously powerful opioid," but that investigators could not determine who sold the "Purple Rain" singer the pill. Authorities fined the doctor who prescribed Prince painkillers in a friend's name.

A week before Prince died, he was treated at Trinity Medical Center in Rock Island, Illinois for an overdose. His plane made an emergency landing in Moline after he had played a show in Atlanta, and he was briefly hospitalized after overdosing on the plane.

The suit by the six heirs to Prince's fortune accuses the doctor who examined the entertainer of misidentifying the pain pill the singer took before his overdose as a Vicodin, when it was instead a counterfeit laced with fentanyl, the Minneapolis Tribune reported. The suit also accuses the hospital of failing to appropriately identify and treat the overdose.

The probable heirs of Prince's estate are split between two lawyers who competed in court on Thursday to represent their interests in managing his estate. Both men - CNN contributor and onetime White House adviser Van Jones, and a show business attorney already hired as an estate consultant, L. Londell McMillan – bragged about established ties to Prince as they testified in court. Their differing backgrounds and priorities have implications for the control and commercial misuse of musical assets left by Prince when he died.

In addition, the suit names Walgreens because it gave prescriptions meant for Prince to his longtime friend and manager Kirk Johnson.

"We will have much to say when the time is right," the attorney who filed the suit on behalf of the family, John Goetz, told the Star Tribune.

“We have client interests to protect at the moment, including our theory of the case. What happened to Prince is happening to families across America. Prince’s family wishes, through its investigation, to shed additional light on what happened to Prince,” Goetz said.

Prince was 57 when he died on April 21, 2016, at his Paisley Park home of an accidental overdose, six days after the overdose on the plane.