The Corpus Christi Massacre, Corpus Christi Thursday Massacre, or El Halconazo (The hawk strike, so called because of the participation of a group of elite Mexican army soldiers known as Los Halcones) was a massacre of student demonstrators in Mexico City on June 10, 1971, the day of the Corpus Christi festival.
From his earliest days in office, President Luis Echeverría Álvarez announced intentions to reform democracy in Mexico. He immediately allowed some leaders of the 1968 student movement to return from exile in Chile and released many prisoners over the course of two years. In April 1971, the press spoke of coming reforms in education and soon figures such as José Revueltas and Heberto Castillo, both jailed for two and a half years, resurfaced in the political arena. Students were excited and thought they would have the opportunity to return to the streets to demonstrate discomfort against the government. The conflict at the University of Nuevo León gave them a reason to do so: At the end of 1970, teachers and university students presented a basic law that proposed a joint government, and in March 1971 Héctor Ulises arrived at the rectory under the new law. The state government disagreed and slashed the budget, which angered university officials and led to the University Council's passage of a new bill that virtually abolished the autonomy of the institution. The university went on strike and called for solidarity with other universities. The National Autonomous University of Mexico and National Polytechnic Institute immediately responded and the students called for a massive rally in support of Nuevo León on June 10, 1971.
On May 30 the governor of Nuevo León, Eduardo A. Elizondo Lozano, resigned as part of the settlement of the Ministry of Education. With the governor's resignation, by June 5, a new organic law came into force that resolved the conflict. Nevertheless, students decided to march even if the demands were not clear. The committee coordinating committee control-CoCo-was divided as there were those who thought that the march was useless and would only provoke the government. However, most people supported the law, arguing that there were many unresolved problems. It was also an opportunity for the government to show that it would not be as repressive as before. Days before the demonstration many police vehicles and cars started making regular runs near the Casco de Santo Tomás (one of the IPN's main campuses).