By Salvador Edgardo Zuniga Cáceres

It has been four months since the murder of environmental and Indigenous rights activist Berta Cáceres and her killers have still not been brought to justice. Instead, the violence continues—on July 7, another activist from Berta Cáceres' organization was abducted and killed.

Berta Cáceres in 2015.Goldman Environmental Prize / Tim Russo

In March, my mother Berta Cáceres was murdered in her own home. Her death pains me in a way I cannot describe with words.

She was killed for defending life, for safeguarding our common goods and those of nature, which are sacred. She was killed for defending the rivers that are sources of our people's life, ancestral strength and spirituality.

My mother became a woman of resistance, of struggle, so that our deep connection with nature is not destroyed; so that the life of our peoples—the Lenca Indigenous People of Honduras—is respected. Her killers tried to silence her with bullets, but she is a seed, a seed that is reborn in all men and women. She is a seed that will be reborn in the people that follow her path of resistance.

To achieve justice for her death, I need your help.

Please join me in asking the Honduran President Juan Orlando Hernández to launch an independent investigation into my mother's murder.

Berta with her four children.

Honduras is one of the most dangerous countries in the world for environmental activists—more than 100 were murdered between 2010 and 2014.

These figures make me shiver. These activists lost their lives defending what belongs to us all and my mother was no exception. She had been threatened and persecuted many times for safeguarding our people's territory.

Even before my mother's murder, two of my sisters had to leave the country. But our mother did not stop fighting against the Agua Zarca mega-dam project. If built, the Agua Zarca would lead to the displacement of our people and the privatization and destruction of our territories. It has already led to the murder of those who have the determination and the clarity to understand that life is not a commodity.

But the dam builders could not stop my mother. With her people beside her, she became invincible. So murderers broke into her house and opened fire against her chest. We are outraged not only because of the bullets that murdered her, but because her killers have walked away with impunity.

Berta Cáceres in the Rio Blanco region of Honduras.Tim Russo / Goldman Environmental Prize.

Berta used to say: "Defending human rights is a crime in Honduras."

She knew that what she put her and her loved ones at risk, but she didn't care. Along with the Civic Council of Popular and Indigenous Organizations of Honduras—an organization my mother co-founded—she defended Indigenous communities and gave her life. Today, our family, the Lenca people and thousands of Hondurans are demanding justice.

We will only succeed if we press my country's president into accepting that the Inter American Commission on Human Rights investigates the murder. We cannot trust the Honduran justice system.

"You have the bullet … I have the word. The bullet dies when detonated, the word lives when spread." —Berta Cáceres

Today, we must be that word. My mother gave her life defending humanity and the planet. Now it's up to us to seek justice on her behalf.

Salvador Edgardo Zuniga Cáceres is the son of award-winning Honduran activist Berta Cáceres, who was murdered in her home in March 2016.