On December 4, 1963, a shooting occurred inside the Brazilian Federal Senate in Brasília, resulting in the death of substitute Senator José Kairala (PSD-AC). The incident arose from a long-running political rivalry between Senator Arnon de Melo (PDC-AL) and Senator Silvestre Péricles (PST-AL), both from politically prominent families in the state of Alagoas. Tension between the two families had grown as their political influence increased, with the Péricles family having held regional and federal office for longer, while the Mello family would later gain more prominent standing, including the eventual presidency of Fernando Collor de Mello, Arnon de Melo's son.
The article states that Péricles had been provoking Arnon de Melo, prompting Arnon to begin carrying a firearm for self-defense. Despite having attended few Senate sessions, Arnon de Melo was reportedly goaded by Péricles into attending the session of December 4, 1963, and did so while armed. Péricles, aware of the risk, also came to the session armed. During the session, Arnon de Melo requested the floor and spoke about threats he said he and his family faced. When Péricles began to advance toward him, Arnon de Melo fired his weapon. Péricles reportedly threw himself to the ground and drew his own gun, but was prevented from firing by another senator, João Agripino, who intervened.
In the aftermath, it was discovered that a third senator, José Kairala, had been struck by gunfire while apparently trying to break up the confrontation. Kairala, from Acre, was sitting in as a substitute for Senator José Guiomard, who was dealing with a health problem, and this was reported to be Kairala's last session in the Senate; he had brought his wife and children to attend. Kairala died at the hospital later that day. The Senate session was canceled indefinitely by its president, Auro de Moura Andrade, because of the incident.
Following the shooting, both Arnon de Melo and Silvestre Péricles were taken to a police station to give statements. Arnon de Melo remained in custody for a period, still in possession of his revolver, before being released with a promise to appear at a subsequent hearing. At that hearing, he was released on grounds of self-defense, and Kairala's death was officially treated as an accident. Kairala's widow reportedly sought to have Arnon de Melo cover her son's school expenses, but this request was unsuccessful.
Two other historical incidents involved Brazilian legislators using firearms against colleagues: a 1929 shooting by congressman Ildefonso Simões Lopes, who was acquitted, and a 1967 shooting involving deputies Nelson Carneiro and Estácio Gonçalves Souto Maior, in which both men survived and were later acquitted.