An Indianapolis law firm has filed one of the first suits in the nation seeking class-action status in its case against mortgage lenders and servicers who used questionable tactics in thousands of home foreclosures.

The federal lawsuit was filed Tuesday by Cohen and Malad, which specializes in class-action cases. The case comes as the smoldering foreclosure issue threatens to erupt into a national crisis for the mortgage industry.

Attorneys general in all 50 states are jointly investigating whether lenders violated state laws. And on Wednesday a federal law enforcement official said the FBI is trying to determine whether the financial industry might have broken criminal laws in pursuing mortgage foreclosures.