What is the law on personal property landlord refuse to give back?

Not in most states.

No.

Of course they can.

I want to return my building back to the bank. We are uncertain as to how we can do this or if it is even possible. We have a three flat and we owe a substantial amount of money on the property and...

Yes, no matter if your lease states it or not, the landlord can legally do this if you're behind on rent: http://leg1.state.va.us/cgi-bin/legp504.exe?000+cod+55-230