CNN reported that the pain-killing substance was found on Prince while the Star Tribune in Minneapolis reported that prescription pills were found where the musician died at the age of 57 last week at his home in suburban Minneapolis.

Both reports were based on unidentified law enforcement sources. Reuters could not independently confirm the reports and local law enforcement officials were not immediately available for comment.

Various news outlets including CNN also reported that local enforcement has requested the U.S. Drug Enforcement Administration to assist in the investigation.

Police have said they found no signs of suicide or obvious trauma in the death of Prince and that it could take weeks before autopsy results reveal how the groundbreaking performer died.

The Star Tribune said that authorities are trying to determine what, if any, role opioids may have played in Prince’s death whether the drugs found at the scene were prescribed to him.

The intensely private musician, whose hits included “Purple Rain” and “When Doves Cry,” was found dead in an elevator at his home in suburban Minneapolis last Thursday, shocking millions of fans around the world and prompting glowing tributes by fellow musicians.

Also on Wednesday, a judge in Carver County, Minn., acting on a request from Prince’s sister, Tyka Nelson, named Bremer Trust, National Association as special administrator to handle his estate, which is estimated at hundreds of millions of dollars.

Prince’s sister asked for the bank to be appointed, saying it dealt with the singer’s affairs for years.

A probate hearing in the case was scheduled for May 2, according to state court documents and a court spokesman.

The Bremer Trust now has the authority to manage and supervise the late music legend’s assets and determine the identity of his heirs, the court documents said.

Prince, born Prince Rogers Nelson, was married and divorced twice. Nelson on Tuesday listed herself and five half siblings as his heirs.