Prince died from an opioid overdose, a source told the Associated Press (via the BBC).
The legendary singer died on April 21, and more than a month later tests reveal he passed away from a drug overdose. At the beginning of May, the investigation into Prince's death took a turn when the U.S. Attorney's office and Drug Enforcement Administration joined the efforts.
"The U.S. Attorney's Office and DEA are joining the Carver County Sheriff's investigation," a spokesperson for the U.S. Attorney's office told E! News.
"The DEA and U.S. Attorney's Office are able to augment this local investigation with federal resources and expertise about prescription drug diversion. While this remains an ongoing investigation, we will have no further comment."
The two agencies' involvement in the investigation came shortly after the Minneapolis Star Tribune published a report that said the "Purple Rain" crooner was supposed to meet with a California doctor who specializes in addiction. Prince was allegedly suffering from an addiction to pain killers and had representatives reach out to Dr. Howard Kornfeld, a national authority on opioid addiction treatment, because Prince was "dealing with a grave medical emergency," said William Mauzy, an attorney working with the Kornfeld family.
But Kornfeld couldn't clear his schedule, so he sent his son, Andrew Kornfeld, in his place. Andrew works with his father at Recovery Without Walls in Mill Valley, Calif. When Andrew arrived at Prince's beloved home, Paisley Park, Prince couldn't be found.
The medical examiner began Prince's autopsy the day after he was found dead. At the time she said it could take "several weeks" to determine a cause of death, but authorities ruled out foul play and suicide.
After his passing, Prince's ex-wives, Manuela Testolini and Mayte Garcia, held a private, star-studded memorial in which close friends and family could pay tribute to their fallen friend. Shortly after his death, many celebrities, including Spike Lee, Beyoncé and Jennifer Hudson, honored the "When Doves Cry" singer with performances and dance parties.