The brutal Bangkok crackdown that was hushed up for years
5 October 2016 Last updated at 00:33 BST
When Thai soldiers opened fire on students demonstrating at Thammasat University in Bangkok they killed at least 46 people, effectively ending a brief period of democracy in Thailand.
The brutal killings that took place on 6 October 1976 were quickly swept under the carpet and not investigated by the new military authorities or discussed for many years.
Thongchai Winichakul was one of the student leaders on the campus. He spoke to Witness about the attack that haunts him to this day.
Witness: The stories of our times told by the people who were there.