Ad Age is out with a story today about an unidentified marketer that spends hundreds of millions on ads that has been subpoenaed by a grand jury in connection with the ongoing Justice Department-FBI probe into media-buying practices. The investigation began last year.

It’s not clear when the subpoena was issued — The Wall Street Journal published a story last fall indicating that subpoenas were being issued back then in connection with the investigation.

Read the full MediaPost article here.