The Internal Affairs bureau has arrested a 29-year-old Brooklyn cop amidst accusations that he repeatedly had sex with a minor for the past five years, starting when she was 10 years old. According to initial reports, the girl is related to off-duty officer Jacques Mackenson, who was arrested just after midnight today. He was to be arraigned in state court in Brooklyn on rape, sex abuse and other charges. The sex crimes allegedly began in 2005 and continued until last spring, after the girl turned 15, investigators tell the Associated Press. (NY1 reports that the abuse started three years ago when she was 12.) Mackenson reportedly joined the NYPD in 2008, and was assigned to a housing project patrol. He's now suspended without pay.