¿Quién mató a Tendetza?

Was this indigenous leader killed because he fought to save Ecuador's land? 

http://www.theguardian.com/world/2015/jun/02/ecuador-murder-jose-tendetza-el-mirador-mine-project

José Isidro Tendetza Antún’s battered body was found in an unmarked grave and loved ones blame his death on his opposition to $1.4bn Chinese-backed mine