Here is what the victim remembers: she arrived at her boyfriend’s house in a Rio favela at about 1 a.m. She was alone with him there. Then, she woke up in a different house, in pain. The men – there were a crowd of them, some with guns, and she would eventually count 33 – had delegated two to hold her down. They were taking turns to rape her. When they finally let her go, she was naked and bleeding. She found some spare clothes and then walked home; they had also taken her bag. In the video that the 20-year-old suspect Michel Brasil da Silva posted to Twitter, a man stands beside the victim’s unconscious body as she stirs.