The news of Saleh's brother Rohullah Azizi being killed, came days after the Taliban forces took control of the provincial centre of Panjshir, which is the last area to be holding out against them.
Ebadullah Saleh said in a text message, "They executed my uncle. They killed him yesterday and would not let us bury him. They kept saying his body should rot."
The Urdu account of the Taliban information service Alemarah said that, according to reports Rohullah Saleh was killed during a fight in Panjshir.
Saleh, (a former head of the National Directorate of Security), which is the intelligence service of the Western-backed government that collapsed in August, is at large, though his exact location is still unclear.
The National Resistance Front in Afghanistan (grouping opposition forces loyal to the local leader Ahmad Massoud), has vowed to continue opposing the Taliban even after the fall of Bazarak, Panjshir's provincial capital.