A Brazilian rancher charged with ordering the murder in 2005 of American nun and Amazon defender Dorothy Stang has been sentenced to 30 years in jail for homicide.

Vitalmiro Bastos de Moura had been tried three times before but his lawyers appealed and the supreme court annulled Moura's latest conviction. The high court said he was not given enough time to prepare his defence during the trial in 2010.

Prosecutors contend that Moura and another rancher hired gunmen to kill Stang. The defence said there was insufficient enough evidence linking Moura to the crime and planned to appeal.

Stang, born in Dayton, Ohio, spent three decades trying to preserve the rainforest and defend the rights of poor settlers who confronted powerful ranchers seeking their lands in the Amazon's wild frontier. She was gunned down in February 2005 with six shots fired at close range from a revolver.

The trial began and ended on Thursday night in a state court in Belem, the capital of the Amazonian state of Para. State prosecutors said the trial moved quickly because it was Moura's fourth and most of the legal processes had been dealt with in previous trials.

The court also convicted another rancher, Regivaldo Galvao, of ordering Stang's murder. Last year, the supreme court ordered his release, saying he had the right to remain free pending the outcome of his appeal. He was sentenced to a 30-year jail term in 2010.

Earlier this year, Stang's confessed killer was released from jail after serving less than nine of his 27-year sentence. A Para state judge said Rayfran das Neves Sales was entitled to serve the rest of his sentence under house arrest.

Another man charged with taking part in Stang's killing is in prison, and a fifth suspect is at large.

The northern Brazilian state of Para is notorious for land-related violence, contract killings, slave-like labour conditions and environmental destruction.

More than 1,200 people, including activists, small farmers, judges and priests, have been killed over attempts to preserve the rainforest in the past two decades, according to the Catholic Land Pastoral, a watchdog group that tracks rural violence in Latin America's largest nation.

The killings are mostly carried out by gunmen hired by loggers, ranchers and farmers to silence protests over illegal logging and land rights. Yet killings over land are seldom punished.