People Exclusive 
 
 Prince May Have Struggled with a 'Serious Illness' Before Sudden Death, Source Says: 'People Close to Him Were Very Concerned' 
 
 
 
 
 
 An autopsy scheduled for today will help determine what caused the star to 
 
 
 
 Though a report in 
 
 
 
 "The people close to him were very concerned for his health and indicated he'd been undergoing treatments which made his immune system weak," the source tells PEOPLE. 
 
 
 
 Spike Lee Hosts Street Party To Celebrate Prince 
 
 The Purple Rain icon's death comes a week after his private plane made an 
 
 
 
 Although the privacy-loving star generally kept mum about his personal life, collaborator and friend 
 
 
 
 "The thing that really bothers me about it is the Prince I know was super-healthy, vegan, wasn't an abuser of drugs, wasn't an abuser of alcohol," he said. "He was clean and he looked young and he looked really healthy and vibrant so the whole thing is really mysterious to me." Prince may have been struggling with an "ongoing illness," which weakened his immune system prior to his shocking death Thursday at age 57, a source tells PEOPLE.An autopsy scheduled for today will help determine what caused the star to collapse in an elevator at his beloved Paisley Park estate.Though a report in TMZ claims that Prince had been hospitalized for a drug overdose less than a week before his death, a source who worked with him a few years ago believes he was grappling with a serious and ongoing illness at the time."The people close to him were very concerned for his health and indicated he'd been undergoing treatments which made his immune system weak," the source tells PEOPLE.The Purple Rain icon's death comes a week after his private plane made an emergency landing , and the star was rushed to a hospital in Moline, Illinois, but released three hours later. His rep told PEOPLE at the time that the star was still fighting a prolonged battle with the flu.Although the privacy-loving star generally kept mum about his personal life, collaborator and friend L.A. Reid said told the Today show on Friday that his pal was "clean" and a committed vegan."The thing that really bothers me about it is the Prince I know was super-healthy, vegan, wasn't an abuser of drugs, wasn't an abuser of alcohol," he said. "He was clean and he looked young and he looked really healthy and vibrant so the whole thing is really mysterious to me." 
 
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 Disqus ||||| The final flight that a stricken Prince took from Atlanta last week made an emergency landing after an "unresponsive male" was reported on the plane, a source with direct knowledge of the incident told NBC News. 
 
 Few details have been released about the circumstances surrounding that unplanned stop — adding another layer of mystery to the superstar's final days before he was found dead Thursday at his Minnesota estate. 
 
 An autopsy of the 57-year-old "Purple Rain" singer was completed early Friday afternoon, and his body will be released to family as authorities try to determine what caused his death. Results, however, might not be released for several weeks, Martha Weaver, a Midwest Medical Examiner's Office spokeswoman, told NBC News. 
 
 Related: Prince Recovering After Plane Makes Emergency Landing 
 
 A representative had said he was not feeling well at his Thursday night show in Atlanta and his health worsened after he boarded a plane after midnight for Minneapolis. He was reportedly suffering from the flu, and had to cancel other shows. 
 
 The private jet he was on was diverted about 300 miles before reaching Minneapolis to Moline, Illinois, according to flight records and statements made by Prince's publicist last week. 
 
 The only flight scheduled from Atlanta to Minneapolis — and with a diversion to Moline — was a Dassault Falcon 990 jet operated by Executive Jet Management "Jet Speed." ||||| Prince Percocet Triggered OD Days Before Death 
 
 Prince: Percocet Triggered OD Days Before Death 
 
 EXCLUSIVE 
 
 Prince had OD'd on Percocet days before his death, and he ingested so much, EMTs had to administer a "save shot" at the airport where his plane made an emergency landing to save his life. 
 
 Sources in Moline, Illinois tell TMZ, Prince's entourage told responders he had taken the painkiller after his Atlanta concert which triggered the emergency. 
 
 Percocet is a painkiller which contains a combination of acetaminophen and oxycodone, an opioid. It is highly addictive. 
 
 We're told Prince was taking painkillers for a hip problem. We're told he had corrective surgery for his hips around 2010. 
 
 As we reported, Prince went to his local Walgreens 4 times in the week leading up to his death. We got a photo of Prince in the parking lot of the Walgreens hours before he died. Witnesses say he was pacing and agitated, waiting for someone to bring out his meds. ||||| Prince Alarming Pharmacy Runs ... Indicate Secret Health Crisis 
 
 Prince: Alarming Pharmacy Runs ... Indicate Secret Health Crisis 
 
 EXCLUSIVE 
 
 Prince hit up a local pharmacy hours before he died -- the 4th time he visited this week -- indicating his health was far worse than the simple flu. 
 
 TMZ obtained this photo of Prince leaving a Walgreens near his home in Minnesota Wednesday night at around 7 PM. 
 
 Our sources tell us Prince had frequented the Walgreens for years -- but last night, people at the store were concerned because he looked much more frail and nervous than usual. 
 
 As we previously reported, Prince's team told the media he was suffering from the flu. It seemed odd, because his private jet had to make an emergency landing in Moline, Illinois last Friday, just 48 minutes from his home. 
 
 Prince was hospitalized ... but was discharged after only a few hours. Our sources in Moline told us at the time they felt Prince left the hospital way too soon because he was "not doing well" and needed further medical care. 
 
 On Saturday, the day after he was released from the hospital, Prince took the stage at a dance party near his home and curiously said, "Wait a few days before you waste any prayers." 
 
 Prince died Thursday morning. Officials are investigating the cause of death.
– TMZ earlier reported that it was an opiate overdose, not the flu, that led to Prince's emergency landing and hospitalization last week, and now the gossip site is naming the alleged opiate involved: Percocet. Sources tell TMZ Prince took so much of the highly addictive painkiller that when his plane landed, he was given a "save shot" at the airport. Heavy explains that's a shot of Naloxone or Narcan, the drug used to reverse the effects of an opioid overdose. TMZ says Prince was taking painkillers for a hip issue; he reportedly had hip surgery in 2010. A source tells NBC News that when the plane radioed in the medical emergency to request an emergency landing, an "unresponsive male" was reported. TMZ also says he visited a local Walgreens four times this week, including for the last time on Wednesday night, just hours before his death. At that visit, "Witnesses say he was pacing and agitated" in the parking lot, "waiting for someone to bring out his meds," TMZ says. A source also tells People that Prince was apparently dealing with an "ongoing illness" prior to his death: "The people close to him were very concerned for his health and indicated he'd been undergoing treatments which made his immune system weak."