A year on, few answers from probe into Prince's death

According to the warrants, authorities searched his estates as well as looking through the star's mobile phone records and email accounts.

According to a search warrant issued on April 21 previous year - the day Prince was found dead - investigators found several pills labeled "Watson 853".

Some pill bottles had Prince's long-time friend and estate manager Kirk Johnson's name on them.

The details from those documents show the possible direction of the criminal investigation into Prince's accidental overdose death nearly exactly a year ago, a death that left fans around the world heartbroken and bewildered. In October 2016 it was termed "an active homicide investigation" in the documents, but no one has been criminally charged. The medical examiner's office said his death was the result of an accidental overdose of the opioid fentanyl.

Hydrocodone and acetaminophen were found in different bottles in the residence.

Some of the pills seized at Prince's home were mislabeled as hydrocodone when they were really the opioid fentanyl, the strongest painkiller on the market. His death shocked fans and led to tributes worldwide. Documents unsealed Monday don't say how Prince got the fentanyl that killed him, and Tamburino says finding the answer to that will be the target for investigators. Did he know what he was taking? During a search warrant executed at Paisley Park on April 21, the day Prince was found dead, a suitcase was found in Prince's bedroom next to his bed. Dr. Schulenberg met with Prince and prescribed him Clonidine, Hydroxyzine Pamoate and Diazepam, according to the search warrant.

During the interview, Kornfeld told police he arrived at Paisley Park around 6 a.m., planning to meet with Prince.

They don't reveal answers, but do shed light on Prince's struggle with addiction to prescription opioids in the days before he died.

The suitcase also contained the lyrics for "You got the Look", which appeared to be in Prince's handwriting.

CNN's attempts to reach Johnson on Monday were not immediately successful.

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Schulenburg is a local doctor who was employed at North Memorial Medical Center.

Prince was 57 at the time of his death.

Kornfeld told investigators Bekure and Johnson began search for Prince in the studio.

He was found unresponsive in an elevator at Paisley Park, his home and recording studio in Chanhassen, Minnesota.

The affidavits and search warrants were unsealed in Carver County District Court as the yearlong investigation into Prince's death continues. The search warrants don't reveal the outcome of the email searches.

Just six days before he died, Prince fell ill on a plane and made an emergency stop in IL as he returned from a gig in Atlanta.

Kirk Johnson, a drummer for Prince who was with the music icon during his tumultuous last week, spoke to CBS News' Jamie Yuccas earlier this month.

Experts say it's natural authorities would want to speak with Johnson, given his proximity to Prince. Recovery Without Walls is a California-based prescription drug and alcohol addiction program run by Dr. Howard Kornfeld. The goal was for the younger Kornfeld to help evaluate Prince's health and encourage him to enter treatment for pain management and potential addiction issues, attorney William Mauzy told reporters. It is the last time he is seen in public.

Musician Prince was found dead aged 57 at his Minnesota estate just days after being rushed to hospital.