Know-How Exchange : Other

I had a cashier stealing from me for about three years before we caught her. She stole cash, by creating a 4th shift (we have 3, 8 hour shifts, operating 24 hours/day - 7 days a week). For example the "4th" shift would end with a $500 credit. The "real" 3rd shift would start with $500s and the cashier pocketed that amount of cash from customers. and her shift would balance. Also, she was running credit cards through twice.

What other techniques are out there that I should be award of?

Arlene