I'd have assumed it was a bike which got involved in some sort of front-end prangage necessitating new bars, stem and brake levers, and was then rebuilt with parts from the back of a mate's shed/gumtree/ebay/local classifieds - in anything other than the first case there probably is a 50/50 chance they're stolen, but bought in good faith. And the stem, wherever it comes from, is ugly IMO.