Marilyn Baptiste, a councillor with the Xeni Gwet'in First Nation and the winner of the prestigious 2015 Goldman Environmental Prize, penned an open letter demanding international agencies to investigate the death of Berta Cáceres, an Honduran Indigenous leader and environmental activist who was gunned down on March 3, 2016 at her home.

Cáceres was killed only a week after being threatened for her opposition to a hydroelectric project.

"It is truly unbelievable this is possible in 2016," Baptiste wrote over Cáceres' death. "A woman, rightfully standing up as a voice of her people and Mother Earth, murdered in her own home. Days before International Women's Day, a global day celebrating the social, economic, cultural and political achievements of women."

Cáceres was also honoured with the Goldman Prize in 2015 for her work leading the Lenca Nation's fight against the Agua Zarca dam that was planned to be built, despite popular opposition, on the Gualcarque river. The river is considered sacred and vital for the survival of aboriginal communities and her campaign forced Chinese giant Sinohydro and the International Financial Corporation to withdraw from the project.

Cáceres' work was recognized around the globe, but that didn't protect her from being attacked in "the deadliest country in the world to defend the natural world," according to Global Witness.

"The Organization of American States’ Inter-American Commission on Human Rights (IACHR) and the United Nations Human Rights Commission (UNHRC) have a responsibility to protect the Indigenous rights – human rights - of the Lenca and must investigate the assassination of our friend Berta," Baptiste writes. She also asks Prime Minister Justin Trudeau to intervene and demand the IACHR and the UNHRC to do something about this case.

"We share the responsibility to oppose violence against women and girls at the community, national and international levels. Is it right to murder an Indigenous woman who spoke out for protection of a people, a land, water and all of life for her children and grandchildren?", the Canadian Indigenous leader said.

Baptiste's letter was supported by Grand Chief Stewart Phillip and Chief Robert Chamberlin, as well as Chief Judy Wilson and Coola Louis of the Union of B.C. Indian Chiefs.