Amir Sarfaraz alias Tamba, an accused in the brutal killing of Indian death row prisoner Sarabjit Singh in Kot Lakhpat jail in 2013, was killed by unidentified gunmen in Lahore on Sunday, news agency PTI reported, The report said Tamba, a close associate of Lashkar-e-Taiba terror outfit founder Hafiz Sayeed, was attacked by motorcycle-borne assailants in the capital city of …