The former Princess of Qatar has been found dead at her home in Marbella, Spain.
The Spanish and French media report unanimously.
Accordingly, Kasia Gallanio is said to have died of a drug overdose.
An autopsy is scheduled for this Tuesday.
The Spanish newspaper El Mundo writes that no traces of violence were found on the body.
The French newspaper Le Parisien first reported on the case.
The police became aware on Sunday when a daughter of Gallanio contacted her mother in vain for days.
The 45-year-old American of Polish descent is the former wife of 73-year-old Abdelaziz bin Khalifa Al-Thani, uncle of the Emir of Qatar.
Gallanio was the third wife of Khalifa Al-Thani.
Gallanio fought a custody battle over her children with her ex-husband amid allegations of incestuous sexual touching.
The French judiciary had recently rejected their applications pending a psychological report.