Berkeley police are warning Bank of America customers to be on the lookout for thieves who are stealing funds when people inadvertently leave their cards in the bank machines.

Police have arrested two men in connection with the broad-based scam, but warn there are other thieves out there. Police arrested Nau Macminh, 38,and Jason Miller, 41, for allegedly withdrawing funds that did not belong to them from Bank of America  ATM machines.

The thieves are taking advantage of people’s forgetfulness. Often, bank customers withdraw money from an ATM and walk away without retrieving their cards.

There have been 23 reported cases of this type of crime in 2010, with an average loss of $400, according to Sgt. Mary Kusmiss. The thieves often park in front a bank machine and pretend to talk on the phone or panhandle in front of the bank. When the customer walks away, the thief accesses the account.

Bank of America is putting more security guards around its ATM machines, according to Kusmiss. The bank has also increased the volume of the beep that alerts  customers that their cards are coming out of the machine.

There are six  Bank of America branches in Berkeley, including those within the UC campus.

Police are informing customers to call 911 when they see a crime in progress. Community members with information about the crimes can call 510-981-5100.

Frances Dinkelspiel, Berkeleyside and CItyside co-founder, is a journalist and author. Her first book, Towers of Gold: How One Jewish Immigrant Named Isaias Hellman...