Prince's estate is estimated at $300 million.
New court documents say Prince had no will.
Read: Newly Surfaced Video Shows Prince Playing 'SNL' Afterparty
The musician "died intestate" - meaning he did not specify what should happen to his estate, his sister, Tyka Nelson claims.
In a court document, she says her brother has "substantial assets," but did not list them. Recent estimates have valued his estate at $300 million.
Nelson listed herself, three half-brothers and two half-sisters as heirs.
She asked the court to name a special administrator to oversee her brother's assets.
Meanwhile, reports surfaced claiming the celebrity's half-siblings had worried in the past about his alleged abuse of cocaine and the painkiller Percocet.
Read: Was Prince Awake For 154 Hours Before His Death?
Lorna and Duane Nelson have since died, but their attorney, Michael Padden, spoke to the Minneapolis Star-Tribune about his client's alleged concerns.
“Both were really concerned it would end his life prematurely,” he told the newspaper.
Watch: The World Sees Purple in Tribute to Prince
