PHNOM PENH: Cambodia’s UN-backed Khmer Rouge war crimes tribunal gave its final verdict on Thursday, upholding the genocide conviction and life sentence imposed on former head of state Khieu Samphan.The court said the 91-year-old was also guilty of multiple crimes against humanity for his role in the genocidal ultra-communist regime, which wiped out some two million people through starvation, torture, forced labor and mass executions between 1975 and 1979.