Bernard Madoff, founder Wall Street's Bernard L. Madoff Investment Securities, was arrested by Federal Bureau of Investigation agents for alleged fraud, according to The Wall Street Journal.

Madoff allegedly told senior employees on Wednesday that the company was "a giant Ponzi scheme" after trying to distribute the "couple of hundred million dollars" he had left before turning himself in, according to the Journal, citing sources.

The extent of investor losses wasn't immediately clear, the Journal said on its Web site Thursday. The alleged scheme reportedly involved tens of billions of dollars. The Securities and Exchange Commission is expected to file charges, too.

Earlier Thursday, a prominent New York lawyer accused of selling sham investments to hedge funds in a separate case, was denied bail.

Marc Dreier, founder and sole equity partner of Dreier LLP in New York, is believed to racked up losses exceeding $380 million, prosecutors said in court.

Dreier is in custody.