Mexican authorities have arrested a retired general and three other soldiers on suspicion of involvement in the disappearance of 43 students in southern Mexico in 2014, the government said.

Assistant Public Security Minister Ricardo Mejia said that among those arrested was a former officer who commanded an army base in Iguala, Guerrero state, in September 2014 when the teacher training college students were kidnapped, ABC News reported.

Mejía did not name those arrested, but the commander of the Iguala base at the time was Jose Rodriguez Perez, then a colonel. Just a year after the students disappeared and when the families of the missing students were already raising suspicions of military involvement and demanding access to the base, Rodriguez was promoted to brigadier general.

A government official confirmed that Rodriguez had been arrested and said he was being held at the military base. Of the others arrested, the source said only that two were officers and the third was a private.