The coroner's office will conduct an autopsy on the body of Christian Brando at the request of his family, authorities said.
Brando, the troubled son of the late actor Marlon Brando, died on Saturday at a Los Angeles hospital. An attorney representing Marlon Brando's estate said the 49-year-old died from pneumonia.
His family requested the autopsy yesterday "based on his past drug history", Los Angeles County coroner's Lt Fred Corral said.
The autopsy, including a toxicology analysis, was scheduled for today, Corral said.
Also yesterday, Christian Brando's ex-wife Deborah sued the executors of Marlon Brando's estate, claiming she is a victim of professional negligence, fraud and deceit.
She claimed that, as part of a February 2007 settlement with Christian Brando in a domestic violence case, she would become assignee of her ex-husband's rights and claims in the estate.
Deborah Brando accused producer Mike Medavoy and fellow executors Larry J. Dressler and Avra Douglas of executing a forged codicil to Brando's will days before his death in July 1, 2004.
"The will was forged ... designed to separate and alienate (Deborah Brando) from others in Marlon Brando's close and extended family, friends, and business acquaintances, and to keep them from challenging the will or trust," the lawsuit said.
Christian Brando was the eldest of the actor's nine children, according to a will the Oscar-winner left following his death in 2004.
Brando's mother was actress Anna Kashfi. She and Marlon Brando divorced after a year.