Juan Maino was an engineering graduate from Universidad Técnica del Estado (State Technical University) and a militant and dirigent of the Movimiento de Acción Popular Unitaria.
He was working on his thesis in mechanical engineering with classmate Antonio Elizondo Ormachea.
Maino was arrested by DINA agents on the night of May 26, 1976, at the Elizondo apartment, in Ñuñoa, Santiago, together with Elizabeth Rekas Urra.
The latter was pregnant at the time and her husband, Antonio Elizondo, had been detained earlier that same day around 6:30 p.m. at the intersection of Alameda Avenue and Lord Cochrane Street, in downtown Santiago.
[4] According to witnesses, Maino and Rekas were detained by at least three agents in one car, who remained at Elizondo's house past 2.00 a.m. Days after his disappearance, Maino's mother presented a habeas corpus to the 8th Criminal Tribunal of Santiago.