The sentencing on Thursday of seven men accused of murdering the Honduran environmentalist Berta Cáceres is only partial justice, but it should inspire anyone committed to ending the slaughter of land and nature defenders around the globe.

A court in Tegucigalpa handed down guilty verdicts on all but one of the eight accused, including two employees of the hydro-electric dam company that the indigenous Lenca woman had been campaigning against before her assassination on 2 March 2016.

The Goldman environmental prize winner was shot in her home by armed intruders along with Gustavo Castro, a Mexican environmentalist, who survived by pretending to be dead.

The judge ruled the murder was carried out by a gang of hitmen on the orders of executives of the Agua Zarca dam company Desa, who were frustrated at costly delays caused by the protests.

A number of those accused of murdering environmental leader Berta Caceres in a courtroom in Tegucigalpa. Photograph: Orlando Sierra/AFP/Getty Images

Two Desa managers were sentenced: Sergio Ramón Rodríguez, communities and environment manager; and Douglas Geovanny Bustillo, the company’s former security chief.

Yet the verdict has not fully satisfied Cáceres’s family, who believe the prosecutors imposed a ceiling on who they were willing to hold accountable for the killing. They are convinced the masterminds are still at large because high-level authorisation would have been needed for the killing of such a globally renowned activist.

The trial has been tainted by highly dubious procedures. Castro, the only witness to the killing, was not invited to testify, though he offered to fly to Tegucigalpa to identify the assassin. The Cáceres family’s lawyers were also barred from participating and their access to the evidence has been restricted.

The most senior executive implicated - Roberto David Castillo, who was executive president of Desa at the time of the killing, is still awaiting trial. He and Desa have denied any wrongdoing.

Senior politicians and powerful families who were involved in the construction of the dam have not been called to account. There has also been inadequate focus on the international financial institutions who initially refused Cáceres’s request to stop providing loans to a dam that was opposed by local people. Dutch bank FMO, Finnish finance company FinnFund and the Central American Bank of Economic Integration (Cabei) only pulled out after the murder.

Yet there has been progress of a sort. It is unlikely that anyone would have gone to prison without the huge domestic and international outcry that followed Cáceres’s murder. The vast majority of the 200-plus defender killings in the world each year go unpunished and uninvestigated. A trial of this prominence is almost unheard of and should make those in power think twice in the future about approving assassinations.

For most of the past decade, Honduras has been one of the world’s deadliest countries for land and environmental defenders, according to the watchdog group Global Witness. But there has been a marked decrease in the past year. One reason may be that the powerful interests behind the killings have been given notice that they can no longer rely on impunity.

People honour the late assassinated environmentalist Berta Cáceres with a religious ceremony on the Gualcarque River near Tegucigalpa in 2016. Photograph: Orlando Sierra/AFP/Getty Images

This shows global public opinion can make a difference, particularly when focused through international institutions and NGOs. Cáceres’s murder probably would not have gained as much attention if she had not been awarded the Goldman environmental prize. It would be harder to understand the context without watchdog groups like Global Witness. And the news would have reached fewer people without environmental and human rights campaigning organisations such as Amnesty International, Greenpeace and Human Rights Watch.

Cáceres’s case is also often cited by the United Nations in its efforts to lobby member states to recognise the human right to a healthy environment. This would provide a legal instrument for campaigners to challenge polluters, land grabbers and extractive industries. It would also serve as a vehicle to encourage judges, police and prosecutors to pay more heed to environmental cases.

As John Knox, the former UN special rapporteur on human rights and the environment, noted in a call earlier this year for more support for the defenders like Cáceres: “If we can’t protect them, then how can we protect the environment we all depend on?”