Polajee “Billy” Rakchongcharoen was last seen on April 17, 2014. At the time the human rights activist was working with lawyers in Bangkok to stop the eviction of Karen indigenous people from Thailand’s Kaeng Krachan National park. For five years his wife fought to solve the mystery of his disappearance, suspecting a cover up by local park authorities. But this summer Billy’s body was found burned and stuffed into a 200-litre oil drum which had been dumped in a reservoir on the outskirts of the national park. BBC Thai’s correspondent, Chaiyot Yongcharoenchai, investigates Billy’s murder and discovers how his death could end up helping the families of other disappeared people in Thailand. Producer, Charlotte Pamment. (Image: Billy Rakchongcharoen. Credit: Muenor Rakchongcharoen)