Parents of dozens of missing students called on Mexican authorities Tuesday to investigate the military, while prosecutors said no soldiers were involved in the case that has shocked the nation.
Vidulfo Rosales, a human rights lawyer representing the families, said 10 students, several police officers and members of a drug gang have implicated soldiers in the abduction of 43 aspiring teachers in September.
He said "there are elements" to investigate the military, which has a base in Iguala, the city in the southern state of Guerrero where the students vanished.
But during a meeting between parents, the interior minister and the attorney general in Mexico City, Rosales said officials indicated that there is not enough evidence to open that line of investigation.
Parents and students tried to break into Iguala's military compound on Monday, using a truck to storm through a gate before being repelled by soldiers using tear gas.
Late Tuesday, the director of investigations in the attorney general's office, Tomas Zeron, said 36 soldiers were among 385 people who have made statements in the case.
But he said none of the statements indicate that soldiers or federal forces had any participation in the students' disappearance.
Authorities say the 43 young men were abducted by Iguala police officers on September 26 and delivered to the Guerreros Unidos drug gang, whose henchmen confessed to killing them.
One student has been identified among charred remains found near Iguala, but relatives of the young men refuse to believe they all died.
Iguala's former mayor, Jose Luis Abarca, will face kidnapping charges for the 43 students' abduction, while five officers committed the crime of "forced disappearance," Zeron said.