How do I get the bank to give me information without a fee?

A representative of a not-for-profit that I am working with went to the bank to make a deposit in the NFP's account. When the deposit was attempted, it was discovered that the money in the account (a meager $101) was withdrawn and the account was closed. There were two people authorized to transact business. Although the treasurer (one signer) resigned due to taking a job in another state, we do not believe any embezzlement took place by either of those authorized. The treasurer did have his personal account at this bank and we are wondering if the bank did not just give him the money when he closed his personal account since his name was associated with the account. We want to find out who actually took out the money and go from there (bank's mistake, treasurer's mistake, or theft). The bank will not provide the information without a $40 fee. The bank is holding this information "hostage" in essence; they will not tell us who took out the money unless we pay the $40 fee. How can we avoid this fee and get the information we feel is due? Do we have to take them to small claims court?|||Whatever you do, is the time and effort really worth $100 ?