LARNACA, Cyprus, May 25 (AFP) - Cypriot police said Tuesday that they were investigating the murder of a 71-year-old Belgian woman found stabbed to death in her home here. Police said the body of Ethel Althea Downing was found in her flat in this south coast resort town with multiple stab wounds. Downing, a Belgian national, had lived on the eastern Mediterranean tourist island for seven years, police said.  