Colonial BancGroup is the target of a federal criminal investigation, but it won't affect customers who have accounts, a bank official and a banking expert say.

Colonial, based in Montgomery with four branches in Calhoun County, has told the Securities and Exchange Commission it can't file a second-quarter financial report because of the investigation.

The Justice Department is looking into accounting irregularities at the company's mortgage warehouse lending unit in Orlando, Fla.

Media relations manager Merrie Tolbert said the bank cannot comment on the investigation. Bank officials met with the Alabama Banking Department Monday. The meeting was to ask for Colonial's permission to make the FDIC a receiver for the bank if it becomes necessary.

Tolbert said customers shouldn't be concerned.

"It's a criminal investigation and of course we're cooperating with the investigation," she said. "This will have no effect at all on customer accounts and on customers."

Peter Garuccio, spokesman for the American Bankers Association, said accountholders don't need to worry.

"The bottom line for any depositors, all depositors are insured up to $250,000," he said. "In the 70-plus years history of the FDIC, not one penny of depositor money has been lost."

The Associated Press contributed to this story.