A thirty-year-old woman was arrested after firing ten rounds from an AR-15-style rifle at the Beverly Hills mansion of pop star Rihanna on Sunday.The Los Angeles Police Department captured the suspect in a Sherman Oaks parking lot thirty minutes after several bullets penetrated the exterior walls while the singer was inside.No injuries were reported during the broad daylight attack as investigators from the Robbery-Homicide Division search for a motive following previous security breaches.The motive for the shooting remains under investigation after the high-powered weapon used in the assault was recovered by responding officers.