Making an offer

[Sumit Verma]

I have a quick question.

I'm interested in purchasing a gas station. The gas station is NOT on the market for sale. Long story short - I am positive that owner will sell it if there is offer on the table. I do have owner's company address with me I got it from the county department. 

I am thinking to write a letter to his business/company address, showing the interest and asking for the official books if he wants to proceed. I spoke to the employee for the sales details already but I would to see the books too. Do you think writing the letter is good idea? what other way I can do it?