Thieves used automated teller machines to steal nearly $350,000 from about 300 customers at California's second-largest bank, officials said.

Authorities are investigating whether special cards given to employees of Security Pacific National Bank were used to gain access to accounts, override the daily limit on cash withdrawals and take cash without being detected.The bank reimbursed depositors after discovering the thefts, which occurred Nov. 11-13, bank spokesman Deborah K. Lewis said. She declined to say how many branches were hit.