An Indian national imprisoned in a jail in Lahore has died of tuberculosis, Pakistan authorities said on Thursday, after leading human rights activist Ansar Burney claimed that the death had occurred in 'suspicious' circumstances. Mushtaq Awan, the Superintendent of Kot Lakhpat jail, said Indian national Suraj Singh was mentally deranged and had died on Wednesday of tuberculosis. Singh, a resident of Jaipur, was arrested a year ago.