Finding the Owner, Which Info to trust

[Jerome Harrod II]

Hey, I'm having trouble looking for the owner for a vacant junker.
The example goes like this:
I find a vacant Junker on ABC Street.
I pull the house up in the tax records and got the name of the owner which is Bob.
When I go to switchboard.com or some other "People Finder site" to find Bob's number, it lists all the Bob's in baltimore but for some reason you don't see ABC Street Listed at all with any of the names. Which shows that possibly Bob doesn't own the house.

So When I reverse the address on switchboard.com or some other People Finder Site to find the owner, it says that Bill owns the house instead of Bob.

Has anyone ever found a vacant junker where the tax records and a People Finder site ( like switchboard.com or zabasearch.com) have two different names and numbers as the owner of the house?

Which information do I go by? The Tax Records or The People Finder SIte?
I was thinking of sending a letter to the house with “address correction requested†on the envelope and see what happens.

Any help is greatly appreciated.