The investigation of Prince's death took a turn Thursday indicating that the megastar's collapse on April 21 is now the focus of a criminal probe.

In a three-page incident report, the Carver County Sheriff's Office cited an exception to Minnesota public-records laws that allows it to suppress information relating to a "criminal" probe in deciding to release only scant information about the 911 response to the Paisley Park complex in Chanhassen that morning.

The law says that "investigative data collected or created by a law enforcement agency in order to prepare a case against a person, whether known or unknown, for the commission of a crime or other offense for which the agency has primary investigative responsibility are confidential or protected nonpublic while the investigation is active."

The exception citation doesn't mean that criminal charges will be filed at the completion of the Sheriff's Office inquiry, only that charges are a possibility.

Sources with direct knowledge of the case have told the Star Tribune that they are investigating whether an overdose of opioids led to Prince's death. Prescription pills were found at Paisley Park, but sources have said it was unclear whether they were prescribed to Prince. As part of the probe, investigators also are trying to determine how Prince got the pills, and who may have provided them.

Authorities have said that Prince was alone when he died and that neither foul play nor suicide is suspected.

Carver County Chief Deputy Jason Kamerud, who released the report, said Thursday that the federal Drug Enforcement Administration is not involved in the investigation at this time. Sheriff Jim Olson and County Attorney Mark Metz didn't respond for comment.

The incident report, released a week after the musician's death, provides little detail that wasn't already made public by law enforcement authorities. It doesn't identify who made the 911 call or if anybody in the building talked to investigators after Prince's death.

Timeline of the 911 call

The report did reveal the time frame for the emergency response to Paisley Park that morning. Twenty-four minutes elapsed between the 911 call reporting an "unresponsive adult male" at Paisley Park and Prince being pronounced dead, according to the report.

The 911 call from the music studio was made at 9:43 a.m. Sheriff's deputies and emergency personnel from the Chanhassen Fire Department arrived at the scene five minutes later and found Prince in the elevator.

Emergency responders administered CPR, but were not able to revive the rock star and he was pronounced dead at 10:07 a.m., the report said.

The cause of death was listed as "unknown."

Prince was 57.

His body was cremated last week and a private service held at Paisley Park.

Olson has said a cause of death probably won't become public for weeks, after the Sheriff's Office receives reports from the medical examiner and toxicology results.

The Sheriff's Office released the incident report at the request of media organizations. It also released, upon request, a list of 47 service calls to Paisley Park over the past five years. Four were for medical reasons.

Three of those medical calls occurred within the last nine months, including the final call. It is unclear whether medical calls on Aug. 9, 2015, and Sept. 6, 2015, involved Prince.

Search warrant sealed

Earlier Thursday, a Carver County judge sealed the search warrant in the death investigation.

The request was made by Metz, who stated that the premature disclosure of the details contained in the warrant may compromise the law enforcement investigation by causing the search or related searches to be unsuccessful.

He added that the release of the information could also create a substantial risk of injury to an innocent person or persons or severely hamper the ongoing investigation.

"Due to Prince's status of having been an iconic popular music superstar, there is and will be continued intense media scrutiny upon the manner and circumstances of Prince's death," Metz said in his argument to seal the warrant and any related documents.

District Judge Eric Braaten ordered that the document remain sealed until the commencement of any criminal proceedings or 180 days from the date of Thursday's order.

A search warrant is filed and made public no later than 10 days after its execution. The document typically provides a detailed narrative explaining why a law enforcement agency is seeking the warrant and lists the items or data seized during the search.

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

David Chanen • 612-673-4465