On 2 October 1992 a rebellion erupted in the Casa de Detencao prison in Sao Paulo. Shock troops of military police stormed the prison to quell the rebellion. Eleven hours later, 111 prisoners were dead. In this paper, accounts of the disturbance and massacre are given from the perspectives of the police, the prisoners and the judges who visited the scene. AI also has concerns about the treatment of the wounded and about withholding of information from and abuse of familes of the dead and injured. Official investigations into the incident are discussed and AI's concerns about the forensic evidence are described. Information is given about the prison structure and about the police, including the problem of failure to prosecute for alleged extrajudical executions.