KANO  - Nigeria on Saturday quizzed the alleged kidnappers of two Westerners killed during a failed British-Nigerian rescue bid amid a diplomatic row between London and Rome over the operation. A Nigerian security source said one had confessed to killing Italian engineer Francesco Molinara, 48, and his British colleague Chris McManus, 28, during the assault authorised by British Prime Minister David Cameron on Thursday. The radical Islamist Boko Haram sect, blamed for scores of gun and bomb attacks mainly in the country’s northeast in recent months, has denied responsibility for the kidnappings.