If all of that is true there really needs to be an overhaul of police taking multiple suspicious reports of activity at a home more seriously.
Or there needs to be some kind of coordination between the census bureau, local/state offcials, and various law enforcement agencies.
"You've seen this girl peak out of the attic and with him several times, but never seen the girlfriend over the years? And you claim you saw this girl during 2008/2009, as well as in 2011/2012? There have been 2 separat ereports of female screams from the house over the last 5 years.... hmm... but he marked himself as the only resident of the house on the census in 2010... Furthermore, he is not listed as the guardian of any child in any school in the state, nor has he signed in as the guardian of anyone at any medical facility within the state in the last 10 years..."
I know we have various protections under the 4th amendment, but surely, sharing of information across local, state, and federal agencies (house ownership, school registrations, hospital/doctor sign ins) should allow officials to realize that "Okay, there are screams being heard, and this mysterious girl, whoever she is, doesn't seem to exist or be attached to this guy in any social records, services, or institutions, but she's been there for years according to the neighbors. That calls for a search warrant."
I'm not saying the government should know everything about you, but something as basic as seeing that the guy has never signed for any child or spouse at a doctor, school, on taxes or the census or anything, that should be accessible. And it should be a red flag when you receive numerous incidents where police are notified of screams at his residence over a period of several years.