Moments later, 44-year-old Cáceres was shot dead. Her friend, Mexican environmentalist Gustavo Castro Soto was wounded, but survived the attack.
A report made public this week concluded that a plan to assassinate Cáceres had been months in the making, was not an "isolated incident," and was the result of a conspiracy involving financial institutions, current and former power company executives and employees and members of the Honduran state security agency.
The report is the result of months of investigation by a panel of international legal experts. The group formed at the request of the Cáceres' family and the Council of Popular and Indigenous Organizations of Honduras (COPINH) -- after both raised concerns about the legitimacy of the investigation being conducted by the Honduran government.
In response to that call, five specialists in international human rights law agreed to investigate the killing. They formed a group called the International Advisory Group of Experts (GAIPE).
The GAIPE experts, alongside Cáceres' daughters, made a presentation of the report and its recommendations in Washington on Thursday.
A high-profile environmental activist, Cáceres had been leading the indigenous Lenca community in a campaign against the multimillion-dollar Agua Zarca project.
She was co-founder and coordinator of COPINH and a key figure in the fight against planned construction on the Gualcarque River, home to the Lenca people. Power company Desarrollos Energéticos Sociedad Anónima (DESA), owns and operates the Agua Zarca project -- which has now been put on hold.
After the killing and and "to reduce international and local tensions in the area
," FMO and Finnfund, two of the financial institutions, exited from the Agua Zarca project in July.
Eight arrested in investigation
Eight suspects have so far been arrested in connection with Cáceres' death, according to the Honduran attorney general's office.
They include a former employee of DESA who worked as its chief of security, a manager for DESA's social and environmental issues department, a former Honduran military general and a major in the country's armed forces who was still an active military member at the time of his arrest.
But Cáceres' family and supporters have always maintained that there were many more individuals involved in her slaying. GAIPE's report alleges that company executives from DESA, state agents and officials were involved in planning, executing and attempting to cover up her murder.
Cáceres' daughter, Bertha Zúniga Cáceres, told CNN they are happy with the report's findings.
"One year since the investigation began and 20 months after the assassination -- to have a lead on the plotters of the crime -- a demand that has been a priority, a fundamental priority. There is so much satisfaction," she said.
The report states that strategies used by DESA's, "shareholders, executives, managers and employees," included "surveillance, threats, contract killing, sabotage of COPINH's communication equipment; cooptation of justice officials and security forces, and strengthening of parallel structures to State security forces."
These methods, the report says, were, "to control, neutralize and eliminate any opposition."
Power company DESA has denied any involvement in Cáceres' death.
In an email to CNN, a spokesman for the Agua Zarca project said GAIPE's report was "taken out of context and does not reflect the reality, but has been built with the intention of doing damage to the Agua Zarca project and generating instability in the country 26 days before the (November 26) elections in Honduras."
Agua Zarca had proposed "a Dialogue for Peace Table, aimed at solving the conflict, which GAIPE rejected stating that this is not part of its mission," according to the Agua Zarca statement. The statement also said GAIPE members had confirmed the group was being financed by COPINH, "an organization in Honduras that is promoting certain candidacies in the country," ahead of the elections.
After this article initially published, Agua Zarca issued a new statement to CNN, completely rejecting GAIPE's accusations as false, after the company says they took "a deeper analysis of what GAIPE has published."
"Agua Zarca is totally disconnected from any act of violence and the project works at all times in accordance with the provisions of the Law in Honduras," the company said. "We have not identified a single new fact. WhatsApp and text messages referred to in the report were made available to all interested parties by the Honduran justice in January 2017."
Roxanna Marie Altholz, a GAIPE member who is also associate director of the International Human Rights Legal Clinic at the University of California, Berkeley's law school, told CNN in a phone call that COPINH in no way financed the report.
Agua Zarca, "publishes irresponsible statements and falsehoods," she said, directing CNN to the last page of the 92-page report where the names of funders and acknowledgments are listed. COPINH is mentioned in gratitude for their support, not under the funders.
As for the release of the report being political, Altholz said it was released a year from when the investigation started.
"We decided to release it now because the report was ready now. I don't know if there is ever a good time to release a report about a criminal structure responsible for a murder and a host of other crimes," she said, adding, "this has nothing to do with the election."
'A fraction of the evidence'