FILE - In this March 23, 2010 file photo, police officer Joao Vicente Oliveira attends his trial in connection with the death of American Joseph Martin in Rio de Janeiro, Brazil. In May 2007, Oliveira was off-duty when he detained a boy who'd snatched a purse belonging to a friend of Joseph Martin, who witnesses say intervened and was arguing with Oliveira when the officer fired at him. Oliveira was acquitted in 2010 and was himself gunned down by unidentified assailants several months after the trial, according to news reports. (AP Photo/Felipe Dana, File)