Trinh Xuan Thanh has already been sentenced to life in prison for property fraud while at PetroVietnam Construction Corporation
Dinh La Thang and 21 other defendants are accused
The economic mismanagement at the construction firm resulted in losses of around VND3.3 trillion (US$145.37 million).
Legal proceedings have also been launched against three other PetroVietnam officials
The confession squashed allegations that he was kidnapped in Berlin and forcibly taken to Vietnam
Vietnamese authorities are still investigating the case after Trinh Xuan Thanh turned himself in on Monday
Trinh Xuan Thanh has been evading an international arrest warrant since September 2016