An early investigation - dubbed "the historic truth" - under Mexican Attorney General Jesús Murillo Karam of the government of President Enrique Peña Nieto, concluded corrupt municipal police from Iguala and neighboring towns, following orders from the local mayor, had turned 43 of the students over to the local drug cartel, Guerreros Unidos ("United Warriors"), who killed the students and destroyed their remains, and that Federal police and military played no part in the killings.

[4] The investigation led to the arrest of a dozen soldiers and a former attorney general, but the army and navy continued to hide information,[4] and on 21 February 2024 parents of missing students announced they would cease dialogue with the commission.

Other protest tactics used by the students include throwing rocks at police officers, property theft, road blockings,[18][20] and taking over toll booths to demand payment.

[6] Local authorities in Guerrero tend to be wary of student protests because of historic and suspected ties with leftist guerrillas or rival political groups (see Mexican Dirty War).

[19] In December 2011, two students from the Raúl Isidro Burgos Rural Teachers College of Ayotzinapa were gunned down and killed by the Guerrero state police during a rally on the Cuernavaca to Acapulco federal highway.

The bill aimed to reform Mexican public education, introducing a competitive process for the hiring, promotion, recognition, and tenure of teachers, principals, and administrators and declared that all previous appointments that did not conform to the procedures were null.

[34] Business organizations of Baja California,[35] Estado de Mexico,[36] and Chiapas[37] demanded decisive action against teachers on strike, as well as politicians from the PRD[38] and PAN,[39] and academics.

[41] In January 2014, the governor of the State of Mexico, Eruviel Ávila Villegas, sent a bill to the local Congress proposing to sanction those teachers who were actively protesting and not attending their jobs with fines and jail time.

[43] On September 26, 2014, at approximately 6:00 p.m. (CST),[44] more than 100 students from the Ayotzinapa Rural Teachers' College in Tixtla, Guerrero, traveled to Iguala, Guerrero, to interrupt a DIF conference presented by María de los Ángeles Pineda Villa, then-first lady of Iguala, and following that to commandeer buses for an upcoming march in Mexico City,[45][46] The students had previously attempted to make their way to the state capital Chilpancingo, but state and federal authorities blocked the routes there.

[59][61] "El Cabo Gil" then called Sidronio Casarrubias Salgado, the top leader of Guerreros Unidos, and told him that the people he had in custody posed a threat to the gang's control of the area.

[23] Unforgiving, stubborn, and extremely vulnerable, the families marched once a month through central Mexico City, putting themselves in front of television cameras, shouting, gathering at the entrance to government buildings, and refusing to budge, demanding the return of their sons.

[97] Mexican authorities also claimed that José Luis Abarca Velázquez, the mayor of Iguala and a member of the Party of the Democratic Revolution (PRD), with his wife, María de los Ángeles Pineda Villa, masterminded the abduction as they wanted to prevent them from disrupting campaign events held in the city, although neither of them were put on trial for the students' disappearance.

[98] Soon after the kidnapping, suspicions were raised concerning the potential involvement of José Luis Abarca, the mayor of Iguala; in the past, he had been accused of direct participation in the torture and murder of an activist, while his wife, María de los Ángeles Pineda Villa, was known to be the sister of several known members of the Beltrán-Leyva Cartel.

[131][132] The woman seen entering and exiting the abandoned property was Noemí Berumen Rodríguez, who was arrested by the authorities that day in Santa María Aztahuacán, Iztapalapa, and believed to have aided the couple in their hiding by lending them her house.

In order to properly identify the remains, the federal government turned to a team of internationally renowned forensic specialists from the University of Innsbruck in Austria for help, though there was no definite timeframe for the results.

[170] In July 2020, it was announced that bone fragments found near the location from where the students had disappeared had been tested at the University of Innsbruck and identified as the remains of Christian Alfonso Rodríguez Telumbre (aged 19).

[190] The resultant public report "Double injustice"[191] is an independent inquiry focused on key aspects of the official investigation under the light of applicable international human rights standards, including the blatant evidence of arbitrary detentions and torture on 51 people indicted in connection to the crime.

Although the report explicitly states it does not intend to offer an alternate version of facts nor to identify the perpetrators and their sponsors, it sheds light on the deliberate actions attributable to the PGR to produce "quick results" and solve the crime, which ultimately tainted the investigation itself.

[90] Marc Giuffre, a Chicago-based U.S. Drug Enforcement Administration (DEA) agent stated that his office had discovered an ongoing heroin, cocaine, and cash smuggling operation between Chicago, Illinois and Iguala, Guerrero.

[12] On 6 March protestors driving a pick-up truck smashed open an entrance to the National Palace in Mexico City, while President Lopez Obrador was holding a news conference inside.

"[226][227]On August 26, 2022, Mexican Interior Undersecretary Alejandro Encinas, leader of the Truth Commission, alleged that six of the 43 students were kept alive in a warehouse for days, and then turned over to a local army commander, Colonel José Rodríguez Pérez, who ordered them to be killed.

The federal police were aware of the attack but did not intervene, according to an account put together by investigators "slowly in the course of years", with hundreds of interviews of survivors, eyewitnesses, and participants in the events cross-checked.

[230] The mass disappearance of the 43 students marked arguably the biggest political and public security crisis Mexican President Enrique Peña Nieto had yet faced in his administration.

[233][234] Unlike other high-profile cases that have occurred during the Mexican Drug War, the Iguala mass kidnapping resonated particularly strongly because it highlighted the extent of collusion between organized crime and local governments and police agencies.

On October 20, 2014, masked protesters set fire to an office of a state social assistance program, Guerrero Cumple, in Chilpancingo, burning computers and filing cabinets.

[245]On November 20, 2014, relatives of the missing Mexican students arrived in Mexico City after touring the country and led mass protests demanding action from the government to find them.

[253] A report from Sputnik news agency says that Roman Catholic priest and human rights activist Alejandro Solalinde said in May 2016 that he had interviewed seven witnesses, one of which insisted that the army was involved.

[254] Jan Jařab of the Office of the United Nations High Commissioner for Human Rights in Mexico condemned the torture of Carlos Canto and 33 other witnesses after a video was released on June 21, 2019.

[257] Pablo Morrugares, a journalist for PM Noticias who specialized in drug-related crime, was working the evening of September 26–27 and reported that he had clear evidence of military involvement in the attack on the students.

Cienfuegos defended the refusal of the armed forces to participate in investigations into human rights violations in this case or in the Tlatlaya massacre in Michoacan in July 2014 wherein 22 civilians were killed by soldiers.