All that proves is ownership. It does not prove that the premises were not rented. It doesn’t prove that the squatters are not invited guests. And it certainly doesn’t prove that any deed the squatters produce was not obtained in good faith, either from a third party con-man or from you as a way of bilking them out of their money.
Those are all issues that can only be resolved by a court. It’s way beyond the scope of the police.
No, because the police have no reasonable grounds for arresting any person. Even if you have evidence that a crime has been committed, there is no evidence of who by. As far as the actual evidence goes, it seems plausible that *you *sold the squatters a false deed, and it is *you *who should be arrested.
Of course you can eventually prove otherwise when you can obtain a copy of the deed for expert analysis a can subpoena the squatters and get their testimony. But all that can only be done by a court, not a police officer.
Not as far as I can see, at least not in the short term. Simply claiming to be a tenant or guest is enough. Many people rent property or stay with people without ever signing a lease, and there’s no legal requirement to do so. Leases make it easier to get a court to evict someone, but lack of a lease doesn’t mean that the police can just toss someone out of their home.