Prince was found dead one day before he was scheduled to meet with a California doctor in an attempt to kick an addiction to painkillers, an attorney with knowledge of the death investigation said Tuesday.

Dr. Howard Kornfeld, a national authority on opioid addiction treatment, was called by Prince representatives the night of April 20 because Prince “was dealing with a grave medical emergency,” said William Mauzy, a prominent Minneapolis attorney working with the Kornfeld family.

Kornfeld, who runs Recovery Without Walls in Mill Valley, Calif., could not clear his schedule to meet with Prince the next day, April 21, but he planned to fly out the following day.

So he sent his son, Andrew Kornfeld, who works with him, to Minnesota, with plans for him to go to Paisley Park to explain how the confidential treatment would work, Mauzy said.

“The plan was to quickly evaluate his health and devise a treatment plan,” Mauzy said, speaking on behalf of the Kornfelds. “… The doctor was planning on a lifesaving mission.”

Several other sources with direct knowledge of the investigation confirmed Mauzy’s account. Calls and e-mails to the Kornfelds were not returned Tuesday evening.

Crowds continued to make the pilgrimage to Paisley Park on Monday to honor Prince.

Andrew Kornfeld was expected to meet with Prince early Thursday after taking a red-eye flight from San Francisco the night Prince’s representatives called, Mauzy said.

When Andrew Kornfeld arrived at Paisley Park at 9:30 a.m. Thursday, Prince’s representatives could not find him, Mauzy said. Andrew Kornfeld was one of three people at Paisley Park when the musician’s body was found in an elevator a few minutes later — and it was Andrew Kornfeld who called 911.

Mauzy said that Andrew Kornfeld told him that the others “screamed” when they found Prince and “were in too much shock” to call 911.

Unfamiliar with Paisley Park, Andrew Kornfeld simply told the dispatcher, “We’re at Prince’s house.”

Asked again to give an address, he said simply: “The people are just distraught. … We’re in Minneapolis, Minnesota, and we are at the home of Prince.”

Emergency responders arrived within five minutes. Prince was pronounced dead at 10:07 a.m., 19 minutes after responders arrived.

Authorities said Prince was alone when his body was found. Foul play and suicide are not suspected. Autopsy results, which will include toxicology tests, are pending.

Within days of Prince’s death, sources told the Star Tribune that his use of painkillers, which were found at the scene, had become the focus of the investigation. As part of their probe, investigators are trying to determine where Prince got the pills and who provided them.

While authorities have characterized their work as a criminal investigation, that doesn’t mean that it will result in charges.

After he was first contacted by Prince’s representatives, Howard Kornfeld requested that a Twin Cities physician check on Prince and stabilize him, sources said.

It was hoped that Prince would agree to go to California for long-term care under Kornfeld’s supervision, which would include round-the-clock nursing support, Mauzy said.

Prince’s representatives called Howard Kornfeld because of his reputation as a nationally known addiction researcher, Mauzy said.

According to Howard Kornfeld’s business website, Recovery Without Walls is a “personalized outpatient clinic, specializing in innovative, evidence-based medical treatment for chronic pain and drug and alcohol addiction.” It says that the clinic’s medical team “works together to resolve problems that other clinicians have found difficult, if not impossible to solve.”

Howard Kornfeld also is known as an advocate for the expanded use of Suboxone, which contains buprenorphine and curbs opioid cravings. The drug has been underutilized, in part, because many doctors haven’t completed the federal training that is necessary to prescribe it.

Andrew Kornfeld had a small amount of buprenorphine to give to Prince. However, it was never administered, Mauzy said.

He added that Andrew Kornfeld gave the medication to Carver County investigators, who later interviewed him and the two others — whom Mauzy identified only as Prince staffers — who were at Paisley Park when the body was found.

Attorney William Mauzy answers questions from the media as he arrives at his Minneapolis office Wednesday, May 4, 2016.

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.

Carver County Chief Deputy Jason Kamerud declined to comment Tuesday about the investigation.

Tyka Nelson, Prince’s sister, who in recent days has led the appointment of a special administrator to oversee his estate, also declined to discuss her brother’s death Tuesday.

“I have nothing to say,” she said.

Staff writers Dan Browning, Jeremy Olson and Emma Nelson contributed to this report.