In late July 1973, the PC sent Berger to take over the communications of Chuqui Copper. The family left for Chuquicamata in August, and there, Berger took over as director of Radio El Loa and Hertz began working in the mining company's legal department. On 11 September, the day of the coup d'état, Berger was arrested after continuing radio broadcasts although the new authorities had ordered him to cease them. That night he was released, but hours later, the military raided the house and took him away. Berger was subjected to a drumhead court-martial that sentenced him to 60 days in jail for failing to comply with the order to stop transmissions during the day of the coup. On 17 October, Hertz, who was his lawyer, managed to have the remaining days of the sentence commuted to a fine. But the political prisoners who were held at Calama, including Berger, were taken away and brutally killed by members of the so-called Caravan of Death, an operation directed by Sergio Arellano Stark to eliminate political dissidents from the recently established military dictatorship.