Waldemar Pereira Rivas, known as “Cachorrão,” is a Paraguayan national whose name became prominent in investigations involving organized crime along the Paraguay-Brazil border and the 2020 killing of Brazilian journalist Lourenço “Leo” Veras.
Paraguay’s Public Prosecutor’s Office accused Rivas of intentional homicide and criminal association in connection with the killing of Veras in Pedro Juan Caballero in February 2020. Prosecutors alleged that Rivas was involved as an accomplice and linked him to a criminal structure associated with Sergio de Arruda Quintiliano Neto, known as “Minotauro.” These allegations were contested by the defense.
The Leo Veras case
Rivas was arrested in May 2020 and subsequently prosecuted in connection with the journalist’s death. According to prosecutors, investigators had collected documentary, testimonial and digital evidence that they argued connected him to the crime. The prosecution ultimately requested that the case proceed to an oral and public trial.
In November 2022, however, a trial court in Pedro Juan Caballero acquitted Rivas. The judgment found that the prosecution had not established his criminal responsibility beyond reasonable doubt and ordered his release in that case. The court did establish that the homicide itself had occurred, but found insufficient proof to attribute responsibility to Rivas.
The prosecution appealed the decision. In 2025, Paraguay’s Public Prosecutor’s Office reported that an appellate court had annulled the earlier acquittal and ordered a new oral trial, citing inconsistencies and problems in the original judgment and the evaluation of evidence.
Previous Brazilian case
Rivas has also been associated with a separate criminal case in Brazil. Paraguayan authorities and Brazilian authorities identified him under another name, Waldemar Rivas Dias, in connection with a 2000 robbery and homicide in Dourados, Mato Grosso do Sul.
According to Paraguayan reporting, he was extradited to Brazil in 2008 and served part of a sentence before receiving a semi-open prison regime in 2012. He subsequently returned to Paraguay after violating the conditions of that regime. Brazilian authorities later issued an international alert concerning him.
The case became particularly controversial after his 2022 acquittal in Paraguay, because reports indicated that an Interpol Red Notice connected to the Brazilian case was still in effect.
Alleged criminal connections
Paraguayan prosecutors have described Rivas as being connected to an organized-crime structure operating in the border region. Authorities have also alleged links to the Brazilian criminal organization Primeiro Comando da Capital (PCC). Such descriptions should be understood as allegations or law-enforcement characterizations unless established by a final judicial decision.
The legal history surrounding “Cachorrão” is therefore complex: he has faced serious accusations in Paraguay, was acquitted in the original Leo Veras trial, and later saw that acquittal annulled with a new trial ordered. Separately, Brazilian authorities have pursued him in connection with an older homicide case.
For journalistic purposes, Rivas should not be described as convicted of the murder of Leo Veras. The 2025 appellate decision reopened that case rather than establishing his guilt.
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