Yun Yat, alias Comrade At, was the wife of Son Sen, defence minister of Democratic Kampuchea. On October 9, 1975, the Standing Committee of Communist Party of Kampuchea placed her in charge of information and education inside and outside of the country. In 1977, she was appointed as information minister after Hou Nim's arrest and execution.
On June 10, 1997 Khieu Samphan (former State Presidium Chairman of Democratic Kampuchea) declared that Yun Yat and Son Sen had been arrested as spies of Hun Sen and Vietnam, and declared as traitors. Yun Yat, Son Sen and eight relatives of them were executed on June 15, 1997.