Prince was found dead at his Paisley Park compound just one day before he was supposed to meet with a doctor to help him with his alleged painkiller addiction, according to a published report.

Lawyer William Mauzy told the Minneapolis Star Tribune that representatives for Prince called Howard Kornfeld, a Northern California doctor who specializes in opioid-addiction treatment, on the night of April 20 because the renowned musician "was dealing with a grave medical emergency."

The following morning, Prince's body was discovered in an elevator at his complex in Minnesota.

Carver County Chief Deputy Jason Kamerud told The Washington Post on Wednesday that he could not confirm the Star Tribune report on Prince's addiction-treatment plans, citing an active investigation.

The Hollywood Reporter confirmed that the U.S. Attorney's Office and Drug Enforcement Administration have joined the investigation.

"They have agreed to provide federal resources and expertise in our investigation," Kamerud later told the Hollywood Reporter.

Remembering Prince, a life in pictures

FILE - 21 APRIL 2016: Musician Prince has reportedly Died at 57 on April 21, 2016. LOS ANGELES, CA - MARCH 28: ***EXCLUSIVE*** Musician Prince performs his first of three shows onstage during "One Night... Three Venues" hosted by Prince and held at NOKIA Theatre L.A. LIVE on March 28, 2009 in Los Angeles, California. (Kristian Dowling/Getty Images for

When Prince's team reached out to Kornfeld, a doctor and medical director at Recovery Without Walls, he told them he could not make it out to meet with Prince until April 22, so he sent his son and associate, Andrew Kornfeld, to fill Prince in on the medical care that the clinic could offer him, their lawyer told the Star Tribune.

"The plan was to quickly evaluate his health and devise a treatment plan," Mauzy, who is working with the Kornfelds, told the newspaper. "The doctor was planning on a lifesaving mission."

Mauzy, a prominent Minneapolis attorney, told the Star Tribune that Andrew Kornfeld arrived early April 21 at Prince's home in Chanhassen, not far from Minneapolis. Mauzy said Kornfeld brought buprenorphine, a medication used to treat opioid addiction.

But, Mauzy said, Prince was nowhere to be found.

He was soon discovered inside an elevator — and Andrew Kornfeld dialed 911.

Mauzy said Andrew Kornfeld told him that the other people on the scene "screamed" and "were in too much shock," so Kornfeld made the emergency call.

The Carver County Sheriff's Office recently released a transcript of the call in which a man — now identified by the lawyer as Andrew Kornfeld — told a dispatcher he needed help "at Prince's house."

"So yeah, um, the person is dead here," he told the 911 operator.

Throughout the call, the dispatcher kept asking him to find the address of the home and he continually replied, "I'm working on it, I'm working on it."

"Okay, do we know how the person died?" the dispatcher asked.

"I don't know, I don't know," he said.

Moments later, he alerted the authorities to their exact location.

"Paisley Park," he said.

"You're at Paisley Park; okay, that's in Chanhassen," the dispatcher said. "Are you with the person who's —"

"Yes," he interrupted, "it's Prince."

Six days before Prince was found dead, his private plane was returning to Minneapolis after two concerts in Atlanta when it made an emergency landing in Moline, Ill. Sources with direct knowledge of the investigation have said that the landing occurred because Prince was overdosing on opioids.
Prince's bodyguard carried him to waiting paramedics at the airport and he was given a shot of the opioid antidote Narcan. He was taken to a hospital, but left within a few hours against medical advice.

In the days following Prince's death, such media reports prompted speculation that the musician had been using drugs. Sources told the newspaper at the time that Prince's painkillers were found at the scene.

Prince's longtime lawyer, L. Londell McMillan, has disputed that speculation, telling the Associated Press that although the artist may have taken medication on occasion, he was "not on any drugs that would be any cause for concern."

"People use medication. The question is, are you on meds in a dangerous way?" McMillan told the news agency, adding: "Everybody who knows Prince knows he wasn't walking around drugged up. That's foolish.

"No one ever saw Prince and said, 'He looks high.' It wasn't what he was about."

An autopsy was completed April 22, but the Midwest Medical Examiner's Office said toxicology results could take weeks.

After Prince's representatives called Howard Kornfeld, the physician, he recommended that a local doctor care for the musician until Kornfeld could get to Minnesota, Mauzy told the Star Tribune.

Prince's team hoped the musician would be willing to go to California with him for long-term treatment, Mauzy said.

Howard Kornfeld, described on his website as a "nationally recognized leader in the utilization of the opioid pain medication, buprenorphine," runs a private medical practice in Mill Valley, near San Francisco. His website says he "specializes in the treatment of chronic pain, chemical dependency, prescription medication management issues, and problems with alcohol."

Neither Howard Kornfeld nor Mauzy could immediately be reached for comment.

This story has been updated.