WA POLICE have charged 19 Commonwealth Bank customers over a series of ATM bank frauds after a technical glitch allowed them to withdraw large sums of money, overdrawing on their accounts.

Major Fraud Squad detectives have laid 197 charges over the string of frauds, which happened across WA between December 2010 and March 2011.



Police said the CBA customers withdrew money they were not entitled to during routine software maintenance.



The police investigation, code-named Operation Elvaston, honed in on social networking sites which the offenders used to brag to about the scheme.



Police said it appeared that the offenders had initially stumbled upon the glitch by fluke, but then spread the word through Twitter and Facebook.



More than $200,000 was stolen and another $7 million attempted to be accessed throught the ATMs as part of the scam. In one case, a customer was able to steal $30,000 in multiple ATM transactions.



Det-Const Jennie Ayre said CBA had identified a weakness in its software maintenance systems and the glitch was uncovered during checks of their record keeping. The case was referred to the Major Fraud Squad in May 2011.



"The Major Fraud Squad commenced an investigation and identified Commonwealth customers that had been withdrawing funds in excess of what was in their account,'' Det-Const Ayre said.



Customers were identified through social networking sites and on CCTV at ATM locations.



Det-Const Ayre said said police were seeking numerous other people who had capitalised on the glitch and advised them to contact the bank to arrange a payment plan to repay the money.



"I think it was just a fluke. Someone has found out and it's just spread,'' she said.



"If you don't have the money in the account, it's not yours to take. You are not entitled to the money and it's a criminal offence of stealing.''



The glitch has been fixed.



The charges carry a maximum penalty of seven years' in jail.