I stopped scrutinizing over details like these a few years ago because by and large I found a far more efficient vehicle to carry my equity.  10% on your money with an investment property shouldn't be a stretch at all even if you're poking around the MLS once you consider all of the ways you're making money holding RE [CF, Appreciation, Equity gain, tax benefits..] 

Maybe if they wont go into detail, offer back a seller finance deal comperable to what you would be paying otherwise...

Could you elaborate some details?

@Quinten Sepe, I overlooked that detail.

Please I need advise on builders, cost, duration, financing and every detail possible!

@Michael Facchini - would you mind posting some details for general knowledge?

There’s no mention of how much life is left in major cap-ex items.

For lack of that being provided I request a detailed income and expense statement for each of the last two years that is signed by the seller or their CPA. 

@Bin Chen @Chris Rosenberg Some more details: Turns out the guy who contacted me is actually the seller's agent for the guy next door who is selling his house, and to sell mine would charge a 4% commission. 

Below I have included some of the details that I have, I am going this weekend to view the properties and find out more details:2 Different Duplexes:*$39,000 for Duplex #1 (Assessed at $47,500)*$20,000 for Duplex #2   (Assessed at $36,200)Duplex #1 Rents: *$600 and $400*$600 and $200All In $1,800/month.