The suburban St. Louis-based grocery store chain Schnucks now says that 2.4 million credit cards and debits cards of its customers may have been compromised over a three-month period.

Schnucks announced the breadth of the fraud in a statement Sunday.

Fraudulent charges have come from around the world. The company first learned on March 15 of questionable activity and began an investigation on March 19.

Schnucks pinpointed the problem on March 28 and executed a plan to contain it within 36 hours.

Many customers have questioned why they weren’t informed earlier.

Schnucks says it has learned that the breach began in December.

The majority of Schnucks stores are in the St. Louis area, but it operates in five states: Missouri, Illinois, Iowa, Indiana and Wisconsin.