A group of 13 former heads of Brazil’s Supreme Federal Tribunal (STF) on Monday urged its current president, Justice Edson Fachin, to act upon the ongoing “civil war” crisis at the top court.

The Justices are reportedly demanding that Fachin oversee an “immediate and thorough” public investigation into the court’s conduct in the face of what they describe as the “most acute crisis” in the top court’s recent history.

The Brazilian Supreme Court is currently at the center of a new shocking controversy between Justices Alexandre de Moraes and André Mendonça. The controversy at the Brazil top court began earlier this month after Justice Mendonça unsealed a police report containing an analysis of alleged text messages involving Justice Moraes and Daniel Vorcaro — a Brazilian banker currently under police custody as part of the “Banco Master” case.

According to the report, dozens of WhatsApp messages between Vorcaro and a device allegedly attributed to Justice Moraes were found in a phone seized from the banker at the time of his arrest.

Last week, Justice Moraes demanded an investigation into fellow Justice Mendonça for “abuse of authority” allegedly committed by Mendonça’s actions throughout the ongoing investigations. The escalating “civil war” between the two Brazil top court judges prompted Justice Fachin to demand explanations from those involved in Justice Moraes’ allegations amid the ongoing judiciary crisis.

BBC News Brasil reported that on Monday, a group of 13 retired former heads of the STF wrote a letter to Fachin urgently requesting that a public session is held to address the ongoing controversy, which “has been undermining the prestige and authority of the court.” The outlet obtained a copy of the letter, which reads:

The undersigned retired justices and former chief justices hereby express their full confidence in Your Honor’s integrity, discernment, and resolve in leading this Supreme Court through the most acute crisis in its history, and our absolute conviction that Your Excellency will, as a matter of the utmost urgency, convene a public session so that the full Court may order an immediate and thorough investigation, in accordance with due process of law, of the extremely serious events whose disclosure has been undermining the prestige and authority of this Court, the trust of the people, and even the stability of democratic institutions.

According to the Brazilian outlet Poder 360, who also obtained a copy of the letter, the retired Justices did not directly name Justice Moraes or Justice Mendonça in the joint missive. In a separate Tuesday report, the outlet detailed that Fachin plans to schedule a private meeting at some point this week between him and former heads of the STF who are still serving on the court, with the goal of “hearing their views” on the ongoing crisis at the judiciary between de Moraes and Mendonça.

Speaking on Friday during an official event alongside socialist President Luiz Inácio Lula da Silva, Justice Fachin vowed to enact a “firm, proportionate, and rigorous” response to the crisis at the judiciary.

However, Poder 360 claimed on Tuesday that Fachin is “delaying” a decision on Moraes’ request against Mendonça. According to the outlet, Fachin needs to bring the allegations presented by Moraes before the rest of the top court, who would have to vote on whether or not the allegations merit an investigation.

Fachin gave Justice Mendonça and Prosecutor General of Brazil Paulo Gonet a five-day deadline last week to respond to allegations presented by Justice Moraes, which is set to expire on Friday, September 11. According to the state-owned news agency Agência Brasil, the Justice is still awaiting a response as of Tuesday. Per the news agency, the Brazilian Supreme Court’s own rules state that only the full court has the authority to prosecute and try members of the court itself — but no specific procedure to be followed is detailed.