MINNEAPOLIS — Prince’s six heirs have filed a wrongful-death lawsuit in Illinois stemming from the treatment of the musician in Moline after he overdosed on opioids while returning home from a concert in Atlanta.

Filed just ahead of a legal deadline, the suit makes no specific claims against the Trinity Medical Center in Moline, but argues that a doctor and pharmacist at the hospital failed to appropriately investigate and treat Prince’s overdose.

The superstar singer died a week later, on April 21, 2016, after another overdose. An autopsy found he had ingested fentanyl, a synthetic opioid 50 times more powerful than heroin. Prince was 57 when his body was found in an elevator at his Paisley Park estate.

“We will have much to say when the time is right,” said John Goetz, the attorney who filed the suit on behalf of the family.

A week before Prince’s death, his plane made an emergency landing in Moline after he overdosed on opioids.

Paramedics scrambled to revive Prince on the tarmac after the plane landed. He recovered after two shots of naloxone, an overdose antidote often referred to by its brand name Narcan, investigative records show.