Thats a tough one! Surely the bank will show what went in and what went out, but you will have no way of knowing what money was never deposited in the first place.
Do you have knowledge of what your fundraisers earned? Do the people who chaired events know what they basically earned? Assuming she handed out a treasurers report at each meeting that should state what money was made, but again it may be innacurate as she probably understated the earnings. The vendor information should be more accurate in helping you know what you made.
How long was this person the treasurer? The books of the previous treasurer may prove helpful in giving you a baseline.
It may be impossible to figure it out exactly. Just a thought (becuase I do not know) is it possible to get them on interest lost on stolen money?
Our treasurer of the last two years is currently under investigation for embezzlement. She says 8-10K, but it looks closer to 30+K.
The police were notified and have supoena-ed the bank records and the records from vendors as well, as she either kept no records or destroyed them all.
My question: How does one do an audit with no records available?