FBI agents on Thursday arrested eight police officers accused of planting drugs as fraudulent evidence against residents of housing projects in western Puerto Rico. A raid on the officers' precinct in Mayaguez discovered a safe holding drugs that were kept in reserve to frame people, US Attorney Rosa Emilia Rodriguez said at a news conference. "This is the first phase of a continuing investigation," she said. Agents have outstanding arrest warrants for two other officers, FBI spokesman Harry Rodriguez said. The suspects allegedly used marijuana, cocaine and heroin to frame residents of low-income areas between 2004 and 2007. They also made up elaborate details on arrest and search warrants, Rodriguez said.