The alleged leader of a drug gang implicated in the disappearance of 43 college students killed himself during a confrontation with Mexican security forces Tuesday, a day after protesters demanding an investigation into the students’ whereabouts burned government buildings in the southern state of Guerrero.

Federal forces, which include federal police and military personnel, were carrying out an operation to capture Benjamin Mondragon, or “Benjamon,” the alleged head of the Guerreros Unidos gang in the neighboring state of Morelos, when a gunfight broke out, a federal official said. The official, who was not authorized to be quoted by name, did not say which federal force had taken part in the confrontation.