Chicago-based First American Bank surprised banking analysts with an unusally public debit card fraud announcement released after 18 days of frustration. Their investigation began Feb. 10, when the bank received 11 fraud complaints in one day from checking account cardholders. First American determined that the customers had all experienced fraud right after using their debit cards in Chicago taxis. The bank started shutting down debit cards, issuing new ones and informing customers. At the same time, the bank was trying to get MasterCard and Bank of America to shut down card acceptance in cabs, stop the breach or at least explain what it knew about the problem, but made little headway.