BELLEVILLE, Ill.  — A St. Louis supermarket chain with a store in Bettendorf is facing a potential class-action lawsuit in Illinois related to a security breach affecting up to 2.4 million credit and debit cards of its customers.

St. Louis attorney Jeffrey Millar filed the lawsuit last week in St. Clair County. He filed it on behalf of a man who shopped at a Schnucks store in Belleville during the time the company says customers' accounts may have been compromised.

Maryland Heights, Mo.-based Schnucks Markets has said the breach dated to December and came to light in March. Many customers have reported fraudulent charges, some in the thousands of dollars.

Schnucks has posted a list of the affected stores and specific dates for each store at www.schnucks.com. The company reported that the Bettendorf store may have been affected between Dec. 10, 2012, and March 29.

The Belleville News-Democrat reports that Millar's lawsuit questions why the problem wasn't made public quicker.

A message left Thursday with Schnucks was not returned.