The family of late rock icon Prince has filed a lawsuit against his former doctor, claiming he failed to treat the musician’s opioid addiction.

In April of 2016, Prince Rogers Nelson sadly passed away at the age of 57 from what was revealed to be an accidental overdose of fentanyl.

While it was revealed earlier this year that no criminal charges would be filed over the musician’s death, a lawsuit recently filed by Prince’s family has now taken aim at his doctor, naming him as being ultimately responsible.

In the aftermath of Prince’s death, it was discovered that Dr. Michael Schulenberg has prescribed the painkiller oxycodone to Prince’s bodyguard in an attempt to keep the musician’s identity secret. While he was fined $30,000 for that violation, Prince’s family claim that this is just one example of how Schulenberg failed to properly treat the rocker.

“He failed to appropriately evaluate, diagnose, treat and counsel Prince for his recognizable opioid addiction, and further failed to take appropriate and reasonable steps to prevent the foreseeably fatal result of that addiction,” read the lawsuit, according to ABC.

“These departures from the standard of acceptable medical practice had a substantial part in bringing about Prince’s death.”

As the Associated Press reports, the attorney for Dr. Schulenberg, Paul Peterson, revealed that they plan to fight the lawsuit with all they can.

“We understand this situation has been difficult on everyone close to Mr. Nelson and his fans across the globe,”Peterson explained in a statement. “Be that as it may, Dr. Schulenberg stands behind the care that Mr. Nelson received. We intend to defend this case.”

While an autopsy revealed that Prince had passed away after ingesting a “counterfeit Vicodin pill” that contained fentanyl, a powerful synthetic opioid, no evidence was ever found to say just where Prince had obtained the drug.

After it was revealed that no charges would be filed against Dr. Schulenberg, Prince’s family filed a wrongful death lawsuit against a hospital that had previously treated the musician following an overdose, and a pharmacy for supplying him with “narcotic prescription medication” for improper medical purposes.

The lawyer for Prince’s family, John Goetz, explained of the latest lawsuit, “The Minnesota lawsuit is against all parties whom we now believe share legal responsibility for Prince’s death, but it is possible that we will identify and add other parties as we move forward with the case.”

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