Mexico's federal police collaborated with local forces in the September attack on 43 students whose disappearance and presumed killings have led to mass protests in the country, according to an investigative report published Sunday in the Mexican magazine Proceso.
Federal authorities also likely tortured key witnesses who offered critical testimony for an investigation by the Mexican attorney general's office into the disappearances, the lead reporter for the Proceso story told The Huffington Post.
The Proceso investigation is based on leaked government documents that are not publicly available, as well as a report by the state government of Guerrero, where the students' college was located and where they were attacked. The magazine published an abbreviated version of its story on Saturday, as well as a newswire version on Sunday. The full investigation was published Sunday in a print version of the magazine, only available in Mexico.