(CNN) It was a little before midnight on March 2, 2016, when at least two men kicked in the back door of the home of award-winning environmentalist and activist Berta Cáceres in La Esperanza, western Honduras.

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

Thousands attend the funeral of Cáceres in La Esperanza, Honduras, on March 5, 2016.

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'

Hundreds of Hondurans protest the killing of Cáceres at a march in Tegucigalpa in August 2017.

GAIPE began investigating in November 2016, analyzing texts, GPS information and call logs released by the Honduran attorney general's office.

But the group said it only received a fraction of the existing evidence.

Altholz told CNN that investigators were handed three cellphones, but didn't have access to the phone of active military member Mariano Díaz Chávez.

Chávez, according to a release from the attorney general's office, was among those arrested and is charged with murder. CNN tried to reach out to legal representatives for Chávez and all of those charged, but they could not be reached. No pleas or comments have been publicized.

The attorney general's office has not provided CNN with any details on whether Chávez or any of the other accused have entered pleas in the case.

CNN reached out to the attorney general's spokesman, Yuri Mora, the day before the report was released and he said he was unaware of the report. Mora asked CNN to call him after the report released, but he has not answered multiple calls or social media messages.

"We're concerned with what is happening with the rest of the data," Altholz said.

Berta Caceres at the banks of the Gualcarque River in the Rio Blanco region of western Honduras.

"It's very important that that data be safeguarded because if we were able to come to the very disturbing conclusions based on the small amount of information we were given, we can just imagine what kind of additional information is in the possession of the public ministry."

GAIPE's report also alleges that more people were involved in what it calls a "criminal network" that included members of the Honduran Secretariat of Security -- the country's security agency.

The Secretariat played two roles, the report states: "Failing to protect Berta Cáceres," despite threats to her life, and "deploying personnel and resources for the protection of Agua Zarca project facilities, influenced by its relations with DESA's shareholders and executives."

CNN has reached out for comment from the Secretariat of Security, but again has received no response.

The report also claims that financial institutions backing Agua Zarca, including the Netherlands Development Finance Institution (FMO) and Finnfund, were found to have been "willfully negligent," in failing to respect indigenous communities and their human rights as well as protecting Cáceres.

Cáceres was a tireless campaigner on behalf of the indigenous Lerca people.

joint statement from FMO and Finnfund in reaction to the GAIPE report says they "strongly reject any claim of illegality regarding our role in any project. At all times, we operate within the applicable legal framework," adding, "we regret that we were never consulted for the Gaipe report and we do not recognise the allegations we have come across. We will now study the report in more detail and consider our next steps."

Altholz, of GAIPE, said she believes these institutions were fully aware of the conflicts and bloodshed the project generated. "We know that the international banks had hired on-the-ground consultants to evaluate the conflict and security systems being implemented by the company," she said.

"And this information needs to be made public because they could reveal information about the criminal structure or the criminal network responsible for Berta's murder."

Castro Soto, the friend and environmentalist who was shot and wounded the night of Berta's murder, told CNN he sees positive things in the report which highlight the deficiencies in the investigation.

"The process, and unconstitutional events that happened, it is clear the Attorney General's office was involved," said Soto.

What's next?

While the report's conclusions are seen as a victory by the Cáceres' family and COPINH, Cáceres' daughter, Berthita, said the fight is far from over.

Berthita was elected head of COPINH in June. She said she is satisfied with the report's findings, but will continue to go after whoever was involved in plotting her mother's death. There are leads to those responsible, she told CNN.

"The plotters are powerful people and it's not going to be easy -- not only to have them captured, but to have them stand trial and be punished for having participated in this crime," she said.

Having completed its report, GAIPE has offered its recommendations to the Honduran government and other organizations.

Berta Caceres won the presigious Goldman Environmental Prize in 2015.

"We recommend that the current prosecutors and agents responsible for the investigation be removed, that a new team be put into place that is independent and impartial, that an exhaustive investigation be conducted that identifies, prosecutes and punishes the intellectual authors and the material authors of the crime," Altholz said.

"GAIPE's existence and the struggle for truth and justice in this case really reflects the bravery of the family members, COPINH, and other organizations. COPINH has really suffered unimaginable attacks over the last five years," Altholz said.

"We found evidence of smear campaigns to discredit the organization, through paid informants, hitmen, by sabotaging their communication systems. I have to admire their bravery and determination."

'Deadliest place to defend the planet'

Meanwhile, a watchdog group has warned of growing insecurity in Honduras, especially for environmentalists.

Less than a month after Berthita was elected to head COPINH, she and two other members of the group were in a car pursued by a vehicle carrying men with machetes, Silvio Carrillo, Berta Cáceres' nephew, told CNN.

"After the report is divulged, what is going to happen to COPINH? What is going to happen to my family? The level of threat goes up," Carrillo said.

"Just because we presented this report doesn't mean all is fine. They're just making themselves a target because they must. That's what Berta did. She risked her life."

Berthita said COPINH will not give up.

"We will continue to fight for the truth, for justice, for ensuring this doesn't happen again and for the reparation and fight for Berta Cáceres."

UPDATE: After this article was first published, Agua Zarca issued a new statement to CNN and the story was updated to reflect that. The story was then updated again to embed the Agua Zarca statement and to clarify the departure of FMO and Finnfund from the Agua Zarca project.