Teori Zavascki, a Brazilian Supreme Court justice overseeing parts of the Operation Car Wash corruption investigation involving oil giant Petrobras, was killed, along with four others, on Jan. 19 when the small plane in which he was traveling crashed into the Atlantic Ocean, near Paraty, on the coast between São Paulo and Rio de Janeiro.

Following the crash, President Michel Temer ordered a three-day period of national mourning. On Jan. 23 it was announced that an official investigation into the cause would be conducted. Zavascki, who had kept a low public profile since being named to the 11-member court in 2012, is credited with some of the boldest moves in Brazil’s judiciary history aimed at curbing abuses by influential lawmakers and business leaders. 

The 68-year-old justice was in the process of deciding whether to ratify several plea bargain agreements, including that of contractor Odebrecht, which together with Petrobras owns Brazilian chemical producer Braskem. The decisions, which had been expected for March, could have resulted in public accusations against high profile business leaders as well as political figures, and Zavascki’s family told Brazilian news media he had received death threats.

In Brazil, reports said the justice’s death has raised concerns about the direction of the Petrobras investigation, the independence of the country’s judiciary and the length of time needed for a replacement to continue the probe. President Temer will be able to nominate a replacement, but this would require approval by the Brazilian Senate and could take as long as a year. Justice Marco Aurélio Mello is quoted by Brazilian media as saying the Petrobras investigation “cannot wait that long.” 

The president has already begun talks with potential candidates in an effort  to make an appointment as soon as possible. His choice will be eyed critically in any case, as Temer himself, along with some of his closest allies, has been implicated in the corruption scandal that broke in 2014.  In December, Braskem  agreed to pay fines and indemnities worth $957 million relating to the “car wash” scandal, so named after the filling station that laundered the money.