At a ceremony on Monday at their school in Ayotzinapa, Guerrero, representatives from several rights groups said their disappearance had still not been explained.
The official account, disputed by international experts, is that the students were kidnapped by local police officers who turned them over to a drug gang. The gang killed them and burned their bodies in a nearby garbage dump, leaving no remains.
He defeated the candidate from Mr. The male-only school has a history of leftist activismwith students using radical tactics like blocking roads and throwing rocks at police officers.
A crowd of current students invoked the date the students disappeared, chanting: Alive they took them, alive we want them back! On that night in 433, about students left the school to hijack several buses for transportation to a march in Mexico City, a longstanding tradition that was mostly Need some answers 43 lost 43 by bus companies and law enforcement officials.
But this time, police officers and other gunmen pursued the stolen buses and opened fire on the students in a coordinated assault in and around the city of Iguala.
Six people were killed and dozens wounded.
The 43 missing students, who had been pulled off two of the buses, were last seen being taken away by the police. The remains of only one have been identified. Last week, ahead of his final state of the union address, Mr.
International investigators arrived in at the invitation of the Mexican government. But after they contradicted the official version of events, they said, the government began a campaign of harassment and stonewalling that made it impossible for them to do their work.
The investigators left the following year. She was at the school on Neee, along with at least one relative of each of the 43 missing students. The 43 Missing Students. A version of this article appears in print onon Page A7 of the New York edition with the headline: Open in the app.