Austrian prosecutors say drugs have been found in the blood samples of Rakhat Aliev -- former son-in-law of Kazakh President Nursultan Nazarbaev.
Aliev, 52, was found hanged in his cell in Vienna jail on February 24.
Media reports in Austria cited Austrian prosecutors on February 27 as saying preliminary forensic tests found presence of barbiturates in Aliev’s blood.
Barbiturates are almost completely banned in Austria as drugs making it difficult to suggest that a prison doctor might have prescribed such a medicine to Aliev.
The prosecutors added though that a precise toxicological and pharmacological test results would be available in a few days.
Aliev had been in the Austrian custody since June after turning himself in to Austrian authorities, who charged him in December with the murder of two Kazakh bankers in 2007, a case in which Kazakhstan has repeatedly requested his extradition.
Aliev, a former Kazakh ambassador to Austria who became a vocal critic of Nazarbaev, had denounced the case against him as politically motivated.