Damascus75 plaintiffs testified against Atef Najib.
The verdict sets a legal precedent for prosecuting other officials from the 14-year war.
A Damascus court found Najib tortured Deraa detainees in 2011, sentencing him and the absent Assad brothers to death.
Russia has resisted extraditing Bashar al-Assad from Moscow since his 2024 ouster.
Sources: Al Jazeera Online, The New York Times, Hindustan Times, semafor.com