 The FBI says the shooter was acting alone and used a legally purchased AR-style rifle. The weapon was recovered after 20-year-old Thomas Matthew Crooks was shot dead at the scene. Police in Kenya say they've arrested a serial killer following the recent discovery of at least nine mutilated bodies at a rubbish dump in Nairobi. They say the 33-year-old man confessed to the murder of more than 40 women, including his wife.