U.S. federal prosecutors are conducting a criminal investigation of newspaper tycoon Conrad Black, his former top deputy David Radler and Hollinger Inc., the company confirmed on Tuesday.

Hollinger said in a statement that the U.S. Attorney has joined a lawsuit filed in Illinois by the U.S. Securities and Exchange Commission which charges the defendants with fraudulently diverting funds from Chicago-based Hollinger International Inc. to themselves and to companies they controlled.

Hollinger’s principal asset is its interest in newspaper publisher Hollinger International.