The Cardinal's New York Times obituary is full of vivid detail of the priest's bravery.
In A Miracle, A Universe: Settling Accounts with Torturers, reporter Lawrence Weschler described Arns' role in facilitating secret collection of detailed records of torture and abuse, eventually published as Brasil: Nunca Mais/Torture in Brazil. The horrible story is all there. Like so many torture regimes, the military kept fastidious records of its own misdeeds, never fearing disclosure. Working with Brazilian Presbyterians, Arns created space and helped secure funding for millions of documents to be clandestinely copied, preserved, and published. When Weschler visited Sao Paulo, he belatedly understood what a risk Cardinal Arns had taken: