 In 1963, she was moved to Silthog Thang, a prison 'where those...considered guilty of the most serious crimes were sent,' located between the Mekong (known as the Zachu river in Tibet) and Ngomchu river (a tributary of the Mekong).At Silthog Thang, she was sectioned according to gender and level of devotion.She was also held in isolation for 9 months after refusing to denounce her religion and rebuking an officer.