Kenyan police said on Monday that ivory trade investigator Esmond Bradley-Martin had been found dead in his home by a family member.
The head of the United Nation's Environment Program, Erik Solheim, said he was shocked by Martin's murder and described the late investigator as a "global authority" on ivory and rhino horn trafficking.
Much of his research quantified and analyzed the Asian ivory markets in China, Hong Kong, Vietnam and elsewhere.
Watch video 01:37 China clamps down on ivory trade
A former UN special envoy for rhino conservation, Martin's research was seen as instrumental in pressuring the Chinese government to ban its legal rhino horn trade in 1993 and end legal ivory sales last year, a ban that came into effect on January 1.