Robbery Maps, a site that has been running for many years, has been collating ad-hoc reports from the victims of crime in Barcelona.
The organic submission of incidents has created an interesting matrix of hot-spots.
Take a look yourself (enlarge image by clicking on it), and/or visit here for more.
Via Laietana, Las Ramblas, El Born and Raval feature strongly. Oddly, Parc Guell is quiet. Barceloneta is surely under-represented considering the plague of robberies on the beach there.