The Brazilian Supreme Court Justice overseeing the massive Car Wash corruption investigation died yesterday when a small, private plane carrying him and three other passengers crashed into the sea. Although there is no evidence that the crash was anything other than an accident caused by inclement weather, the circumstances have prompted calls for – and clearly demand – a vigorous and independent investigation, as well as meaningful protection for the corruption investigation to proceed with integrity.

The judge, 68-year-old Teori Zavascki, was appointed to the Supreme Court by impeached President Dilma Rousseff and has managed the corruption investigation process that has sent the country’s richest and most powerful figures to prison, including members of Rousseff’s party. His next step was to be one of the most significant yet: accepting and formalizing the plea statement of top executives of Odebrecht, the construction giant at the center of the scandal.

Those plea statements are widely expected to implicate leading members of the government of Michel Temer, who took over after helping to engineer Dilma’s impeachment, as well as oligarchs and executives, in all sorts of bribery and money laundering transactions. Last year, his son publicly complained of death threats his father had received.

What makes the crash particularly tragic is that Zavascki was one of the few leading figures in Brazil who has proven incorruptible. Indeed, in the infamous recorded and leaked discussions between Temer’s key Senate ally and ex-minister, Romero Jucá, and the executive Sergio Marchado – in which Jucá said that the core purpose of Dilma’s impeachment was to kill the Car War investigation – Jucá explicitly complained that Zavascki was the only Supreme Court justice “closed off” to making deals. As we reported in May when those tapes were disclosed:

The second blockbuster revelation — perhaps even more significant — is Jucá’s statement that he spoke with and secured the involvement of numerous justices on Brazil’s Supreme Court, the institution that impeachment defenders have repeatedly pointed to as vesting the process with legitimacy in order to deny that Dilma’s removal is a coup. Jucá claimed that “there are only a small number” of Court justices to whom he had not obtained access (the only justice he said he ultimately could not get to is Teori Zavascki, who was appointed by Dilma and who — notably — Jucá viewed as incorruptible in obtaining his help to kill the investigation…..

What is perhaps most disturbing about all of this is that Zavascki’s replacement in overseeing the investigation will now be chosen by Temer – the person who has much to lose if a vigorous investigation proceeds. Among other matters, the Court is to decide whether Temer himself should be removed from office due to his participation in the decisions that resulted in Dilma’s impeachment, as well as whether his key allies such as his Foreign Minister José Serra, and perhaps he himself, are guilty of criminal wrongdoing.

All of these circumstances have already prompted calls for a full and independent investigation into this crash. On Thursday night, just hours after news of Zavascki’s death, Transparency International President José Ugaz posted this strong demand: