Kirk A. Johnson, former Prince drummer and best man, may be one of the key persons that can help investigators solve the case. The search warrant that was issued to capture Prince' medical records also revealed that Johnson told the authorities that the late musician visited a local clinic in 2014 or 2015.

According to Yahoo! News, Johnson was also described as Prince' "de factor bodyguard." The 51-year old supposed-to-be-witness is also a personal trainer at Life Time Fitness in Chanhassen but has not reported for work since his friend's passing.

"Right now, it's just too painful to even speak," Johnson reportedly stated. He has not responded to any interview requests.

Also known as Kirky J, his works under Prince also include a cameo appearance on the "Purple Rain" music video. Johnson was also credit for the singer's 11 studio albums. Music and business aside, Johnson is Prince' best man when he married Mayte Garcia on Feb. 14, 1996.

"I'm pretty sure Kirky J knows more about our beloved Prince than any other living soul," a commenter wrote on Prince.org. As for the details of the death, Carver County Sheriff's Office Chief Deputy Jason Kamerud stated that the details are still to be kept under wraps.

Meanwhile, those who are claiming to be the heir to Prince' must prove their legitimacy on the court. As per The Wrap, the special administrator for Prince' estate Bremer Trust asked the judges to require authentic documents as proofs that claimants are really relatives.