When a team of nine employees at the $252 million Widget Financial Federal Credit Union in Erie, Pa., began looking into 10 suspicious accounts in December 2012, they had no idea what they had found.

FBI and IRS investigators eventually uncovered a massive, nationwide fraud case so large, it was “on a scale that is unprecedented,” as one federal prosecutor described it.

The FBI in Pittsburgh on Wednesday announced they indicted five people for allegedly stealing the personal IDs of thousands of people to open thousands of bogus accounts at banks and credit unions across the nation. In some instances, the defendants obtained the names of credit union employees from the cooperative's website or lifted members' names from credit reports to meet membership eligibility requirements, according to the FBI.