In fairness fingerprinting the bike that was left at the scene is not that far out. Police will do that, although it will not prove the job it might highlight a well known sh*t bag who needs his front doors kicked in by the cops to arrest him, but more importantly see what he's got stored at his address.
However there is no need to be negative about the police (JohnClimber that is not helpful). It's not about it being too much like hard work, it's about competing and more important demands/priorities, like for example a burglary scene or photographing the injuries of some poor git who's had his head kicked kicked in during an unprovoked attack.
Flattyres, hope you get your bike back.
All the best,