Brazil's Supreme Federal Court (STF) holds an extraordinary plenary session on Tuesday (Sept. 15), at 10 a.m., to decide whether to open an investigation into Justice Alexandre de Moraes. The justices will examine a Federal Police report that gathered 52 messages exchanged between the justice and Daniel Vorcaro, the former owner of Banco Master and a central figure in the Caso Master scandal, according to news outlet G1.

It is an unprecedented session. According to G1, the full bench will weigh for the first time whether one of its own members should be investigated. On the eve of the ruling, the court still had open questions about the procedure, the quorum and the exact scope of what will be voted on.

How the session will run

The court released the session's rules on Monday (14). According to Folha de S.Paulo, the rapporteur will read the report, the Office of the Prosecutor General (PGR, Brazil's federal prosecution service) may speak, and the votes follow. Court President Edson Fachin will vote first. If any justice asks for a "vista", the Brazilian court rule that grants more time to study a case, the analysis is suspended for 90 days.

Fachin took over the Caso Master relatoria, the rapporteur role, after removing Justice André Mendonça from command of the investigation, Folha reports. As rapporteur, Fachin will present a summary of the facts at issue and set the order of the debates, according to G1.

Tight security

Security will be reinforced inside and outside the court building, according to Folha. The Three Powers Plaza will be closed, and visitors and protesters will not be allowed near the site. The Ministries Esplanade will be blocked at Avenida José Sarney, with fences and police officers, and parking is banned from the Itamaraty Palace onward. The operation brings together forces under the judiciary, the Federal District government and the federal executive, including the Armed Forces and the Institutional Security Office.

Interest extends beyond the court's walls. The FGV law school in São Paulo will gather professors and students in an auditorium to comment on the ruling in real time, according to Folha's Painel column. The session starts at 10 a.m. on Tuesday (15) in the STF's plenary hall in Brasilia, and could open the way for a sitting justice of the court to be formally investigated.