Well, nothing unusual about white vans and if they've set themselves up un a short term rental apt somewhere, those around them wouldn't notice. For all we know, one of them owns a car dealership and has white vans available all the time plus access to plates, etc..
Sac
I still think that every neighborhood has at least one busy body who notices when vehicles are there and gone and that type of stuff. It is just strange to me, but the police are obviously not releasing everything they know either.