It's entirely possible that they feel absolutely sure in the paternity already. Perhaps Hannah strongly resembles other family on the paternal side of the family.
It's possible that Uncle Jim developed an obsessive fantasy that Hannah was his daughter that had no basis in reality.
My middle child and my sister's middle child look more like siblings than they do with their actual siblings and strongly resemble a great grandmother. My youngest is the spitting image of my mother and it was obvious on the sonogram of her facial bone structure in utero.
A simple paternity test would have put that to rest and her DNA was readily available to him for such a test. I doubt that he was the one with the fantasy.
Anything is possible but if Hannah is his daughter then she and not his sister Lora will inherit his property -- thus at this point it is a legal issue amongst everything else.
Also Hannah said regarding her phone that it got burned up in the fire: Can anyone explain how she could have known that despite the fact that no phone was found burned up at the scene???
And if she did leave her phone at the scene then what was she using to make calls to DiMaggio hours later before the phones were turned off???
But by all means the police need to shut down this investigation before they get the truth from Hannah as well as her DNA -- after all there are now more questions than answers. .