Zabalza was taken prisoner on 26 June 1972 alongside eight others, including Eleuterio Fernández Huidobro, for their participation in the Punta del Este robbery.

Interned at the Penal de Punta Carretas [es], he was considered to be one of the hostages of the military dictatorship in Uruguay and endured twelve years of imprisonment and torture.

Following the restoration of democracy in Uruguay, Zabalza became a member of the Movement of Popular Participation (MPP), created by Raúl Sendic.

[2] He began to disagree with Tupamaros such as José Mujica and Huidobro, whose reformist agenda drew criticism from him.

[3] Zabalza resigned as President of the Junta Departamental de Montevideo following a scandal surrounding Arana regarding a transfer of Vaimaca Pirú's remains with France.