In April 1993, a group of Peruvian military officers anonymously released a document detailing the events at La Cantuta. Their document claimed the death squad had abducted the victims, tortured and murdered them, and then hurriedly buried them; later, they claimed, after questions had been raised in Congress, that the armed forces had exhumed, incinerated, and reburied the bodies in another location. The military whistleblowers named the members of "Grupo Colina" involved, identified the operations chief as Major Santiago Martín Rivas, and suggested that the group operated on the orders of Vladimiro Montesinos, head of the National Intelligence Service (SIN) and a close advisor to President Fujimori.