Shukri Ghanem, Libyan prime minister under Moamer Kadhafi, whose body was recovered from the Danube river in April suffered a heart attack before drowning, an official said Tuesday.
Ghanem, 69, succumbed to cardiovascular failure before drowning in the river where he was found on April 29, Vienna state prosecutor's office spokesman Thomas Vecsey told Austrian press agency APA.
The case remains open, with an ongoing investigation into the circumstances Ghanem's death, but third-party involvement has been ruled out.
Ghanem, also a former Libyan oil minister, was living in exile in Vienna at the time of his death after defecting from Kadhafi's regime in May 2011 at the height of the rebellion.
Ghanem had been a top official in Kadhafi's regime, acting as prime minister between 2003 and 2006 and then as oil minister and chairman of the Libyan National Oil Corporation until seeking refuge in Vienna.
Ghanem knew the Austrian capital well from attending meetings of the Organisation of Petroleum Exporting Countries (OPEC), whose headquarters are located there.