Police have arrested a man who is alleged to have sexually assaulted a female British tourist and violently robbed an elderly couple from the UK on the same day. The suspect assaulted the woman in the south of Tenerife after using a martial arts technique called a rear naked choke - or the "lion killer" - which left her semi-conscious, a spokesman for Spain's National Police said. The young woman had lost her mobile phone and the suspect had offered to help her. "Taking advantage of the fact