Following the coup d'état of 11 September 1973, he became involved with the , a non-governmental organization for human rights established by various Christian churches and other religious organizations on the initiative of Roman Catholic Cardinal Raúl Silva Henríquez. Serving as the director of its legal department from late 1973 until the committee was wound up in December 1975, his job was to direct and coordinate the efforts of internal and external lawyers in defending human rights. This entailed work in three broad areas: