In what became known as the Corpus Christi massacre, on June 10, 1971, roughly eight thousand student protesters marched on Mexico City's central square to oppose the government of President Luis Echeverría. A secret police unit called the Falcons (Halcones) attacked the marchers, allegedly killing at least twenty-five people—some that day and others after torture and interrogation. Echeverría ruled the country from 1970 to 1976 during what is often referred to as the “dirty war”—a term used to describe the government's clandestine efforts to crush dissent. Echeverría's government and his party, the Institutional Revolutionary Party (PRI), allegedly used wiretaps, rape, torture, genocide, and extra-judicial death sentences to silence opponents. The media were coopted to prevent the actions of the government from becoming public. Since then, the Mexican government's human rights commission has uncovered numerous stories of horrific acts perpetrated by the secret police, and there is evidence that children born to imprisoned mothers were stolen and that the Falcons were explicitly trained to kidnap, torture, and rape on behalf of the government.