Prosecutors have beefed up their case against a longtime accountant who served as the operations chief for jailed Ponzi king Bernard Madoff.

Federal prosecutors in Manhattan announced that an indictment against Daniel Bonventre was returned Wednesday. The indictment contains a new charge of falsifying records of an investment adviser. He had earlier been arrested on conspiracy, securities fraud and tax charges.

The accountant who worked for Madoff since the late 1960s will enter a plea to the indictment on Thursday. His lawyer, Andrew Frisch, said "the charge is a prosecutorial Hail Mary." He added that his client is "absolutely innocent" and looking forward to the trial.

He has been free since last month on $5 million bail.