"These arrests constitute the first step in a victory over impunity, one that could not be taken for granted given that those arrested are police officers," the press freedom organization Reporters Without Borders said and added:
"For this reason, it is an undeniable advance for the rule of law. But we should remain cautious at this stage in the proceedings and wait to see the exact role that each of these policemen allegedly played in Barbon Filho's death. The trial of his alleged murders should set an example."
The four detained military police members are Capt. Adélcio Carlos Avelino, Sgt. Edson Luiz Ronceiro, his brother, Pvt. Paulo César Ronceiro, and Pvt. Valnei Bertoni.
After investigations were formally opened against them on February 19 on suspicion of homicide, attempted homicide and criminal association, they were arrested on March 4 at the request of prosecutor Gaspar da Silva Júnior of the Special Regional Group for the Prevention and Repression of Organized Crime (GAERCO).
Capt. Adelino is the cousin of Carlos Alberto da Costa, the presumed owner of the gun used in the murder, who had already been arrested. No date has been set for the trial.
Barbon Filho, 37, was in a Port Ferreira bar on May 5, 2007, when two masked men on a motorcycle pulled up outside. One of them went inside and shot twice, hitting the journalist in the abdomen and the back.
According to the victim's widow, Kátia Camargo, he had been the target of repeated death threats shortly before the murder. At the time of his death, he had been investigating a robbery in which members of the local police were allegedly involved.
In a story he wrote in 2003, he accused five municipal councilors and four local businessmen of sexual abuse of teenage girls. They were brought to trial but were acquitted or were given light sentences.