Partner refuses to turn over records

A few years ago I entered into a business partnership with a friend. Because of our friendship and our past business dealings strict documnetation was not adhered to. At this point, my partner has refused to pay the money he owes me for the buyout. The way things have played out, I suspect that he has created deals that are to his advantage and my disadvantage. That is an oversimplied description, but I am simply researching whether this is worth pursuing legally. The bottomline is his lack of transperancy is raising questions of fraud.

Since he is refusing to turn over the financial books, is there a way that I can force him to do so?
If there are some shady transactions, what is a ballpark figure for suing him?

Thanks for any advice,
Michael