The U.S. Justice Department is investigating possibly illegal coordination between U.S. Rep. Michele Bachmann's 2012 presidential campaign and a political action committee involving the Minnesota Republican's husband and other campaign officials.

A Minneapolis Star Tribune report says the U.S. Justice Department has subpoenaed records from the National Fiscal Conservative Political Action Committee. It's part of a federal grand jury investigation.

The subpoena was first reported by The New York Times. It represents a major escalation in the multiple inquiries raised from a campaign whistleblower's allegations of election law violations.

Bachmann representatives and the NFC PAC did not immediately respond to the Star Tribune's requests for comment.

The subpoena covers financial transactions that involve a number of top Bachmann campaign officials, including her husband.