With no obvious signs of trauma to the body and nothing to indicate suicide, Prince's surprise death looks likely to have been the result of a drug overdose, an expert said Saturday.
The 57-year-old superstar was found dead at his estate in Minneapolis Thursday, and autopsy results are not expected to be released until next week.
However, police said Friday that there were no obvious signs of trauma.
The seven-time Grammy-winning artist was discovered slumped in an elevator at his estate in Chanhassen and was pronounced dead at the scene at 10:07 a.m. local time (11:07 a.m. ET) Thursday.
His body was released to family members later Friday.
"I would give overwhelming odds that, tragically, this is a drug death," Cyril Wecht, a forensic pathologist who is not involved in Prince's case, told NBC's TODAY.
"When you rule out foul play, when there is no history of any kind of significant disease … heart and lung … when you rule out any kind of intervention, anything of an environmental nature, you come down to an autopsy that is essentially negative … and that probably means drugs," added Wecht, whose worked on some of the nation's most high-profile autopsies.
He said the emergency landing of the singer's private jet last week for a medical reason "fits into the drug picture."
"I cannot think of any medical or pathological condition that fits that kind of scenario, with incredible ups and downs … other than drugs," he added.
The death was "most regrettable," Wecht said.
The star, born Prince Rogers Nelson, was last seen by an acquaintance who dropped him off at the Paisley Park estate on Wednesday night around 8 p.m., Carver County Sheriff Jim Olson said Friday.
Staff became concerned when they could not get in touch with Prince the next morning, and went to the residence to look for him. They found him "collapsed" in an elevator and called first responders who began CPR on Prince but were unable to revive him, Olson said.
The exact time of Prince's death is pending, said Martha Weaver, a public information officer for the Midwest Medical Examiner's Office.
The call to police was made at around 9:43 a.m. and the sheriff's office, fire department and an ambulance responded, which is "standard protocol," Olson said.
He said some of the responders were carrying Narcan, a drug used as an antidote for drug overdoses, but did not use it.
Prince was found fully clothed on the first floor of the estate, Olson said.
Olson said it appears only Prince was at the estate at the time of his death, but when police arrived three staff members were at the scene.
"Prince is a very private person, and I don't think that that would be unusual for him to be there by himself," Olson said.
The mood when police arrived was "somber," Olson said. "He was a friend, I think, to the people who were there as well as being an employer. They were certainly shook by what had happened."
Olson added that no medical calls came from Paisley Park regarding Prince or within the past year.
Olson reiterated several times that the investigation into the sudden death of Prince at the age of 57 was only 29 hours old, and much was unknown. He said investigators had processed the scene and would talk to people who were close to the music legend and gather medical records. He would not say whether anything was removed from the home during a search.
"There are so many rumors," Olson said when asked to put some of those rumors to rest. "I don't know if I can dispel all the rumors out there."
Prince's family has been cooperative in the investigation, which will be "meticulous," Olson said.