The Wall Street Journal reported Tuesday that the preliminary investigations are aimed at determining whether fraud led to the troubles at mortgage giants Fannie Mae and Freddie Mac, investment bank Lehman Brothers Holdings and insurer American International Group.

Word of the probes comes in the midst of two days of Congressional testimony by Treasury Secretary Henry Paulson and Federal Reserve Chairman Ben Bernanke to push a $700 billion bailout plan to stabilize the financial markets.

ABC News, meanwhile, also quoted FBI sources Tuesday as saying the bureau has 26 pending investigations of corporate fraud involving subprime lenders.

An FBI task force was established following the subprime market crash of 2007 to look at the ways brokers set up and sold mortgage-based securities.

As the depth of the financial crisis and size of the bailout package began to emerge last week, Senate Banking Committee Chairman Patrick Leahy (D.-VT) told FBI Director Robert Mueller at a hearing that he was looking for accountability. "If people were cooking the books, manipulating, doing things they were not supposed to do, then I want people held responsible," Sen. Leahy said.

There has been no immediate reaction from any of the "big-four" firms in the reported investigation.

In the last two weeks, the U.S. government has taken control of Fannie Mae and Freddie Mac, provided and $85 billion loan to AIG and Lehman Brothers was forced into bankruptcy. In each case, mortgage-based securities were a central factor in the collapses. Copyright(c) 2008 RealTimeTraders.com, Inc. All Rights Reserved