Prince's last days: What we know

(CNN) Slowly, the veil surrounding the last days of Prince Rogers Nelson is beginning to lift, offering fans a closer look at the events that led to the singer's untimely death.

On Tuesday, we learned in a search warrant that a Minnesota doctor had seen Prince twice -- the last time the day before the entertainer's April 21 death. Law enforcement sources told CNN that investigators are closely examining the relationship between the doctor, the music legend, and his people.

A look at the last few days of his life provides some clues in hindsight that all was not well.

April 7: Atlanta shows postponed

Fans were lined up outside Atlanta's Fox Theatre for Prince's "Piano & A Microphone Tour" when the news broke: He had to postpone due to illness.

The show promised to be an "intimate" gathering of classic hits, B-sides and "other surprises from his vast catalog."

Fans were upset -- not just because of the postponement, but the reason given by the venue: "the entertainer is battling the flu."

Many worried that a bigger health problem could be afoot; some expressed their anxiety in meme form.

As it turns out, Prince apparently was seeing a doctor that day in Minneapolis.

According to search warrant documents obtained by the Los Angeles Times and Minneapolis Star Tribune, Dr. Michael Schulenberg told investigators that he had seen Prince on April 7.

The documents do not disclose why Prince was being seen by the doctor, who until Tuesday was a family medicine practitioner at a clinic in Robbinsdale, Minnesota.

April 14: The show goes on

A week later, he redeemed himself when he returned to the Fox to perform two 80-minute concerts back-to-back. They were short for Prince, but fans basked in his aura as lavender smoke filled the stage.

The backdrop swirled with kaleidoscopic graphics and pop-art images of the artist. As usual, Prince requested a no-cameras policy during the action; images surfaced after his death showing that many people had trouble adhering to it.

As his royal silhouette appeared to kick off the 7 p.m. show, the crowd's shrieks rivaled Darling Nikki's.

Wearing Summer of Love-inspired bell-bottoms, carrying a cane (he'd long suffered from a bad hip) and crowned by an Afro, he paused at the front of the stage to accept the adulation, according to accounts of the concert.

Taking his seat at a purple piano (technically, a Yamaha digital keyboard inside a grand piano shell, according to the piano maker), he offered a melodic apology for the missed date, then roared into "Little Red Corvette," which segued to a playful rendition of Vince Guaraldi's "Linus and Lucy."

The medley was emblematic of Prince's playful ingenuity.

Despite reports that he was recovering from the flu, illness was undetectable in his full-throated versions of "The Beautiful Ones" and "Nothing Compares 2 U."

"Prince played the audience like a second instrument, bringing us to our feet for 'I Could Never Take the Place of Your Man' and virtually to our knees with his mournful take on Joni Mitchell's 'A Case of You,'" CNN's Melonyce McAfee said.

A second encore included an R&B-tinged version of David Bowie's "Heroes."

"Little did we know the night's second show would be Prince's last public performance," McAfee said. "Now it feels all the more poignant that for one final night, we lived our dream and sang in unison with one of our heroes."

Prince apparently relished the moment, too.

"I am transformed," he said on Twitter the next day.

April 15: An unexpected detour

As he flew back to Minnesota after the performance, Prince made an unexpected stop -- an unscheduled landing and a dash to a hospital in Moline, Illinois.

Afterward, his publicist reassured fans: "He is fine and at home," a statement said, without explaining exactly what happened.

April 16: Biking, Paisley Park dance party

Just hours after the hospital detour, Prince was seen riding his bicycle through the parking lot of a mall in Chanhassen, Minnesota, where he lived.

"I couldn't believe I was looking at him, especially after hearing he had not been feeling well," Kelly Collins told CNN's Kyung Lah.

Later that evening, ever the professional, Prince rebounded for a small gathering of fans at Paisley Park, his home and recording studio in suburban Minneapolis where he hosted late-night concerts and dance parties. Not only did he host but he also performed "to give thanks for the good weather and for all the love and support," he said on Twitter.

Michael Holz, a DJ at many of those parties, was there Saturday. Prince made a passing reference to the emergency landing, he told WCCO.

"He basically said when you hear news, give it a few days before you waste any prayers," Holz said.

The appearance seemed aimed at proving he was alive and well, Minneapolis Star-Tribune music critic Jon Bream wrote the next day.

"I have to leave it in the case, or I'll be tempted to play it," Prince told the crowd of a new guitar, according to Bream. "I can't play the guitar at all these days, so I can keep my mind on this (the solo piano) and get better."

He also unveiled a new, custom purple Yamaha grand piano, which was to be the centerpiece of his tour.

Fans noted that he maintained high spirits even though he appeared frail.

"I just thought he looked really pale and thin, and kind of tired," said Deanne Jensen, who attended Saturday's party. "But he has been thin for a long time."

Mike Rendahl, who was also at the party, said Prince appeared pale but kept the mood light as he showed off his purple piano.

"He seemed like a kid doing show-and-tell," Rendahl said. "You could tell he really liked it."

Again, Prince relished the moment, thanking fans for their "extra time," an apparent reference to his hit song, "Kiss."

April 17: Feeling 'rejuvenated'

The singer replied to a fan on Twitter who'd attended the Atlanta show with the hashtags #FeelingRejuvenated #FeelingInspired and #FeelingLoved.

April 19: Attending a concert

Prince attended a concert at the Dakota Jazz Club & Restaurant in Minneapolis on Tuesday, according to staffer Lucas Harrington. He did not perform.

April 20: Last seen alive

The day before he died, Prince once again saw Schulenberg, according to the search warrant documents published by the Los Angeles Times and Minneapolis Star Tribune on Tuesday. The documents do not elaborate on the reason for the visit, but do indicate that at some point Schulenberg had given the singer a prescription to be filled at a Walgreen's pharmacy. The documents don't reveal what he prescribed.

Around 8 p.m., an unidentified person dropped Prince off at Paisley Park, Carver County Sheriff Jim Olson said. The singer was alone in the complex for the rest of the night, which was normal for Prince, given his private persona, Olson said.

April 21: World loses a legend

A man later identified as Andrew Kornfeld -- the son of a prominent California addiction specialist -- called 911 at 9:43 a.m. Thursday from Prince's estate after employees found a the singer unresponsive in an elevator at Paisley Park Studios.

Kornfeld's father, Dr. Howard Kornfeld, had dispatched his son in a "life-saving mission" to persuade the singer to enter treatment for pain management and possible opioid addiction issues, according to an attorney for the Kornfelds, William Mauzy.

That intervention, however, came too late.

"The person is dead here. ... And the people are just distraught," Kornfeld said as he struggled to find an address to give the dispatcher.

Read a transcript of the 911 call

After paramedics' desperate CPR attempts to revive him, Prince was pronounced dead at 10:07 a.m.

According to the search warrant documents published by the Times and the Star Tribune, Schulenberg also showed up at Prince's estate some time that day, apparently to drop off test results.

August: Public memorial planned

Prince's sister, Tyka Nelson, says the family is working on a public memorial and tribute to the iconic singer in August.