First Deal Due Diligence - What to do?

[Jessica Duckett]

Hey guys, 

I got an email from a wholesaler about a property I'm interested in in Birmingham, AL and don't know where to start on due diligence. 

It's a duplex, first side rented out and says they always pay on time in cash. Second side not rented, but the tenant on the first side is looking to rent both. It's in a C neighborhood, and says they need a new roof. I'm looking to buy and hold. 

I would be able to buy it outright, so I wouldn't need to worry about a mortgage.. just taxes and insurance. 

How do I verify the rent history with the current tenant? How do I get a copy of the lease they're currently under so I can see the terms? I can call a roofer to give me a quote, but beyond that, do I need to wait until it's under contract to get an inspection? How do I make sure the title is clear? Is there anything else I'm not thinking of?

Right now, the only thing I know to do is drive by it and call a roofer for a quote. Any and all help is appreciated! Thanks!