Jon Leibowitz, the chairman of the trade commission, said that "several hundred persons, at least," who were Lifelock customers had become victims of identity fraud while using the company's services. Customers typically paid $10 a month for the services, he said.

Lisa Madigan, the Illinois attorney general, who joined Mr. Leibowitz in announcing the action at a news conference in Chicago, said that while Lifelock did provide some legitimate services, "most of what they did, you can do on your own and you can do it free."