No criminal charges will be brought over the death of musician Prince from an accidental overdose, officials have said.

The announcement comes following a two-year investigation by the state of Minnesota into how the 57-year-old singer died.

Attorney Mark Metz says the evidence shows Prince thought he was taking a drug called Vicodin, not fentanyl.

He explained: "Law enforcement was unable to determine the source of the counterfeit Vicodin laced with fentanyl. 

"Without probable cause and no identified suspect, the Carver County Attorney's Office cannot file any criminal charges involving the death of Prince."

The New York Times reports that the investigation uncovered “no sinister motive, intent or conspiracy to murder Prince".

It was revealed last month that the musician had an "exceedingly high" level of fentanyl in his body when he died on April 21st 2016.

Separately, it has been confirmed that Minnesota doctor Michael Schulenberg - who was accused of illegally prescribing opioids to Prince a week before his death - has agreed to pay $30,000 to settle a federal case.

CNN reports that Dr Schulenberg was accused of prescribing the painkiller Percocet to Prince, but allegedly put the prescription in the name of Kirk Johnson - Prince's friend and former drummer - in a bid to protect the star's privacy.

Officials say Dr Schulenberg did not admit liability in the case, with his lawyer saying the settlement was to avoid any litigation.

Announcing the settlement, US Attorney Greg Brooker said: “Doctors are trusted medical professionals and, in the midst of our opioid crisis, they must be part of the solution."