Guillermo del Toro, Alfonso Cuaron and Alejandro González Iñárritu slammed Mexican officials for their investigation into the disappearance and possible killings of 43 teachers and college students, saying the act and the lack of answers are evidence of systemic corruption in the country.

The three directors who helped attract broader recognition for the Mexican film industry through works such as “Pan’s Labyrinth,” “Gravity” and “Birdman” voiced their criticism in the form of an open letter, which del Toro read during a tribute to Cuaron at the Museum of Modern Art on Monday night.

“The federal government argues that these events are all just local violence,” del Toro read. “Not so.”

“We believe that these crimes are systemic and indicate a much greater evil — the blurred lines between organized crime and high-ranking officers in the Mexican government,” he added.

Mexican authorities have found bones and teeth they say likely belong to the students. An earlier discovery of several mass graves turned out to be a different set of victims.

The students went missing in September after police in Iguala detained them for commandeering public buses in order raise money and transport people to a demonstration. Corrupt law enforcement officials reportedly handed them over to a drug gang in order to prevent the student from overshadowing a speech by the wife of the town’s mayor. The discovery of the mass graves and the government’s lack of transparency and responsiveness has inspired a wave of protests in Mexico.

Cuaron and his son, screenwriter Jonás Cuarón, flanked del Toro at the podium as he read the message. Iñárritu was not present at the event.

“We must demand answers about this and we must do it now,” del Toro read.

The killings and corruption he described seemed a world away from the swank gathering of filmmakers and literary talent such as Julian Schnabel, Salman Rushdie and Katie Holmes. But the directors argued that the crime and terror griping Mexico demanded the attention of the wealthy and powerful assembled in the room.

“We would like to take this opportunity to ask you all to join us in the pain and indignation felt by the families of the disappeared students and of every civilian in Mexico who is living with this atrocious reality on an every day basis and to at least be aware of this systematic human rights violation taking place so often and so close to you,” he concluded.