Mexican police killed three trainee teachers, shot another in the head and another in the face, and herded dozens more into police trucks to what investigators fear was a massacre on a remote hillside, survivors of the incident say.
On the night of Sept. 26, officers that a state prosecutor says have links to a violent criminal gang in the southwestern city of Iguala pursued about 80 members of a nearby teaching college well-known for its left-wing radicalism, witnesses said.
At least three students were killed in a series of clashes that began after the youths commandeered three buses from the city's bus station, the state government of Guerrero said.
Students say the shooting began after they resisted police demands to give up the buses, and that they then fled on foot. Three students were killed and another three people - including a taxi driver, his passenger and a teenage soccer player - also died in the gunfire.
Investigators have since found 28 corpses buried in mass graves on a hillside outside Iguala, in the state of Guerrero. State security officials believe some of the 43 students still missing since the confrontation are among the victims.
The case has undermined President Enrique Pena Nieto's pledge to restore order to Mexico. Drug violence exploded during the rule of his predecessor, Felipe Calderon, and has claimed about 100,000 lives since 2007.
The homicide rate has declined since Pena Nieto took office in December 2012 but kidnapping and extortion are up and the involvement of police in the violence in Iguala has underlined the widespread corruption inside Mexico's security forces.
Guerrero's state government has ordered the arrest of Iguala's mayor, his two top security officials and more than 20 police for suspected involvement in the recent clash. Two of the three, including the mayor, are fugitive and none of them have commented on the allegations.
Fear and disbelief haunts those who witnessed the clashes.
His voice choked with tears, Angel Neri de la Cruz, told of how he saw one classmate shot in the head by police, and another in the mouth.
"The classmate was bleeding so much," the 19-year-old de la Cruz told Reuters at the all-male college in Ayotzinapa, east of Guerrero's capital Chilpancingo. "He wrote on his mobile phone: 'Get me out because I'm dying'. Because he wasn't able to talk."
Both of the injured students survived, classmates said.
De la Cruz and his colleague Uriel Alonso Solis say they saw police officers drive off with between 25 and 30 students in pick-up trucks.
"We saw them take them. It just means that we have a narco government in Guerrero," de la Cruz said, standing in a bright complex of classrooms and dormitories decked out with murals of socialist revolutionaries like Karl Marx and Ernesto "Che" Guevara and other symbols of rebellion.
Hundreds of students briefly occupied the state attorney general's office in Guerrero on Tuesday in protest and a local leftist guerrilla group known as the EPR issued a statement pledging to resist what it labeled "state terrorism".
One of the students who died in Iguala had the skin cut beneath his throat and his face pulled off. State government officials in Iguala said it took hours to reconstruct the face.
"It was really sadistic," one of the officials said.
Juan Rodriguez, a former student at the college, was asked to see the body because he feared it was his missing brother-in-law. It was not.
"Things are even more lawless under Pena Nieto than they were under Calderon," the 33-year-old said.
After the discovery of the corpses outside Iguala, state investigators reported that police had handed over the students to their suspected executioners, local gang members.
Not all the victims can be missing students, because three were female, a local official said. The area where the bodies were buried after being burned on a funeral pyre has served as a dumping ground for enemies of the gang, another official added.
The state attorney general's office said the top city officials in Iguala under suspicion are believed to have links to a gang called Guerreros Unidos, or "United Warriors", and is accusing them of conspiring with the group to kill the students.
The students are often described by Guerrero officials as vandals. Those studying at the college say they depend partly on funds collected on the street and that the buses were taken for use as transportation for trainees among them to give classes.
Some officials speculate that the students may have been manipulated by a rival gang to create unrest in Iguala and weaken Guerreros Unidos. The students rejected this outright and say they may have been targeted by the police as a disruptive threat to an event in the city.