The 1976 military coup, on March 24, resulted in Vargas Aignasse's arrest by provincial police, who had their detainee turn in all documentation regarding the Arrechea case. Days later, his brother, Rodolfo, was allowed to see the prisoner from above a patio, following which, per police testimony, he was released from prison on 5 April and 'kidnapped by parties unknown' while being taken home in an official car. He was later reportedly seen alive and in pain by a number of witnesses, though his whereabouts afterwards remained unknown.