RFE/RL's Kazakh Service reports that the court in Vienna on August 8 refused to extradite Rakhat Aliev on grounds that he would not be guaranteed a fair trial in Kazakhstan.
The decision did not affect a separate Austrian money laundering investigation against Aliev, who is a former ambassador to Austria.
He is wanted in Kazakhstan on charges of abduction, assault, and money laundering.
Aliev says the Kazakh case against him is politically motivated because he intended to run for president within the next few years.
Kazakhstan filed an international arrest warrant against Aliev in May. He was arrested by Austrian authorities in June, and later released on bail.
(with material from agency reports)