It was the bloodiest prison violence in Rio de Janeiro's history, and the worst in Brazil in more than a decade. After 62 hours of terror, in a gang war inside the Benfica detention center, at least 30 inmates and one guard were dead. By Monday morning, June 1, police were ready to storm the facility. At the behest of prisoners however, Rio State secretary of security Anthony Garotinho called in a controversial Pentecostal pastor who has made a name for himself as a prison minister and negotiator. Pastor Marcos Pereira da Silva, 47—leader of the Assembly of God of the Last Days, a church located in São João de Meriti, outside Rio de Janeiro—arrived in a helicopter to end the standoff.

"I managed to avoid a massacre," said the pastor, after the standoff had ended, only a few hours after his arrival. In interviews on radio and television, da Silva described how he managed the situation.

"Coming in, I saw prisoners dangling by the feet, ready to be decapitated," he said. "Others were tied to gas cylinders. There were many with wounds and burns."

Despite the chaos, da Silva said he gathered 700 prisoners in a block. His story, which is difficult to confirm, was reportedly witnessed by 15 assistants accompanying him.

"I said a prayer and many fell possessed by demons," he said. "I prayed and sung praise hymns. Then we took the guns from them before they got back to their cells."

When police entered the building, they found no resistance. While details of da Silva's work inside the prison have not been widely confirmed, several witnesses have reported that the prisoners ended the riot singing Christian praise songs.

"If I did not arrive, a hundred people would have died," the pastor emphasized.

Da Silva said he persuaded ...