The work of Sombath Somphone is well known across Southeast Asia, but his disappearance in Laos on December 15 is a mystery.
It was Sombath's development work and help to poor farmers that won him one of Asia's most prestigious civil service awards.
Laos authorities told Sombath's wife that they do not have him. They say he might have been kidnapped for personal or business conflicts, and an investigation is under way.
Al Jazeera's Scott Heidler reports from Bangkok.