In 1735 he was allowed back to Lhasa to study and teach, but still under strict control, being mistrusted by the Qing, while Polhanas ruled Central Tibet under nominal Qing supervision. Meanwhile, the Qing had promoted the Fifth Panchen Lama to be a rival leader and reinstated the "ambans" and the Lhasa garrison. Polhanas died in 1747 and was succeeded by his son Gyurme Namgyal, the last dynastic ruler of Tibet, who was far less cooperative with the Qing. On the contrary, he built a Tibetan army and started conspiring with the Dzungars to rid Tibet of Qing influence. In 1750, when the "ambans" realised this, they invited him and personally assassinated him and then, despite the Dalai Lama's attempts to calm the angered populace a vengeful Tibetan mob assassinated the "ambans" in turn, along with most of their escort.