My neighbor's packages was delivered to me, but I am going to refuse to give it back.
Why don't you want to give the package to your neighbor?
Because I don't believe that the package belongs to the people who have the house
Even though you have doubts about the people living in a house does not mean you should not give the package to them. The package is address to them so you should give their package to them.
Yes but I'm not sure that they actually belong to the house so I'll hold the package in hopes of finding out who the real owners of the package are.
That's not your decision to make. If it was delivered there, you need to give it back regardless of who is living there.