An intriguing and probably unsolvable case...my specialty! Once you take away the "supernatural" elements emphasized on so many websites, what we have here could be a case involving illegal immigration, espionage, or organized crime. "Bella" seems never to have officially existed in the UK, but during wartime that wasn't so unusual. The most complete treatment (albeit a little bit occultish) is at http://www.mysteriouspeople.com/Bella_in_the_wychelm.htm. I wonder what DNA would tell us...if "Bella's" location is even known today?