Elected in 2012, Mayor José Luis Abarca and his wife have long treated Iguala as their fiefdom. In recent years, they have acquired 31 houses and apartments, nine businesses, and 13 jewelry stores. The Mexican Army donated part of the land on which the couple built a $23 million shopping center on the edge of town. At different times, state and federal prosecutors have accused Pineda’s parents and three brothers (two of whom have been murdered) of running an organized crime group known as Guerreros Unidos, or the United Warriors. In Iguala, the widely held view is that the police and the Warriors are synonymous. Pineda once threatened a reporter in public, telling him, “If you keep it up, I’ll cut your ears off.” Abarca has been accused of murdering a local activist named Arturo Hernández Cardona in 2013. A witness testified before federal prosecutors that Abarca shot Cardona in the chest and face. Cardona had been missing for four days when his tortured body was found on the side of the road.

Among those who did not know the accusations against Iguala’s political couple or that they were speaking at a rally a few blocks away were the nine students impatiently waiting for the bus driver to return. They watched him, as he continued to talk with the station’s security guards, who in turn spoke into their phones and radios. Fearing that the driver would refuse to get back on the bus, the students called their compatriots out on the highway, whose response was swift: They gathered rocks, got back on their two buses, and headed for the station.

When they arrived, the students parked the buses on the street and charged the station, their faces covered with T-shirts tied over their heads. The nine waiting students abandoned their bus and, along with the others, commandeered three more. Now aboard five buses, the police nowhere in sight, the students told the drivers to get them out of town as fast as possible. Two buses drove east toward Periférico Sur Avenue, which skirts the center of town and offers a direct route to the highway. The other three buses went north on Galeana Street toward the Civic Plaza. Ignoring the students’ demands to speed up, the lead driver cruised slowly down the street. By this time it was around 9:30 p.m. At the political rally, the talking was over, and the band had started to play.

As the three buses passed the Civic Plaza, police trucks approached from the side, sirens flashing. One truck pulled in front of the first bus, bringing the caravan to a halt. Students jumped off to clear the truck out of the way. More police arrived and started firing in the air. The students of Ayotzinapa presumed that fighting with the police was a kind of cat-and-mouse affair: If you were caught, you would be beaten and arrested, but being gunned down was not part of the game. They rushed forward, pelting the police truck with rocks and forcing its driver to pull back.

“I was in the third bus. When we heard the gunshots, we jumped out into the street,” Ernesto Guerrero, a first-year student, told me. “One of the second-year students said, ‘Don’t be afraid. They are shots in the air.’ But as we approached, we realized they weren’t shooting in the air. They were shooting at the buses and at us. So we decided to defend ourselves. I found four rocks and threw them.”

With the path clear, the three buses drove by the plaza and down Juan N. Álvarez Street, which runs some 15 blocks before it reaches Periférico Norte Avenue, a major thoroughfare. Police trucks pursued, along their side and from behind, firing repeatedly. The buses were a few yards from the intersection with Periférico Norte when a police truck cut them off. This time, the driver abandoned the truck. When students on the lead bus started to push the truck out of the way, police opened fire. A student named Aldo Gutiérrez Solano was shot in the head. In the confusion, the students who were moving the truck almost ran him over. “They finally saw him on the ground, bleeding from the bullet wound in his head,” Edgar Yair, a first-year student, told me. “We wanted to pick him up, but instead of the police letting us lift him, they fired more intensely at us.” At that moment, the students realized, everything changed. The presumed rules disintegrated.

The students ran, some jumping back onto the first bus, others hiding between it and the second bus. More police arrived, firing but not coming closer. Students shouted for an ambulance. When one finally arrived, the police prevented it from approaching, but the ambulance circled back, and paramedics took Solano to the hospital, where he was pronounced brain dead.

Most of the police had massed at the rear, behind the third bus, trapping the students inside. “After awhile, we heard screams,” Jorge Vázquez, a first-year who hid in the back of the lead bus, told me. “I peeked through a window and saw where the police were piling a number of compañeros in the police trucks and taking them away.” During the next 90 minutes, survivors say the police forced the students from the third bus to lie facedown on the street, hands behind their heads, before loading them into the back of police trucks and driving off. These account for 25 to 30 of the students who have not been seen since.

While this attack was occurring, the two buses heading directly out of Iguala became separated. One bus, with 14 students, found itself behind a bus carrying members of the Avispones, Chilpancingo’s third-division soccer team, which had won a game against Iguala earlier that day and was on its way home. “We were at the last overpass,” Alex Rojas, who was among the 14 students, told me, “when we saw beneath us, right beneath us, a bus and a whole lot of police trucks with their mounted machine guns in front of the bus.” This was the fifth bus. The students on it are among the missing.

Seeing the blockade, the driver of Rojas’s bus tried to turn around when police came speeding up and forced him to halt. The students abandoned the bus and began to walk in the opposite direction. Behind them, they heard the police shouting, “Get the fuck out of here or you will be dead!” Pursued by the police, the 14 escaped into a nearby field. In the ensuing three hours, they tried to reach the three buses on Álvarez Street but were prevented by the police, who shot at them and chased them up a hillside, where they hid until morning. Gunmen hunted down the bus carrying the soccer team on the highway to Chilpancingo and killed the driver, a 14-year-old player, and a woman riding in a taxi passing by, and wounded at least nine others.