Investor Jeffry Picower, described as the biggest beneficiary of Bernard Madoff's fraud, is now being sued for $7.2 billion, $2 billion more than the trustee in the case demanded in May.

Picower, newly listed as one of the 400 wealthiest Americans by Forbes magazine, was complicit in the fraud, trustee Irving Picard said in court documents on Wednesday responding to the investor's motion to dismiss his lawsuit.

"Picower makes the paradoxical argument that he could not have been complicit in the Ponzi scheme because he made too much money from it," Picard wrote in the filing in U.S. Bankruptcy Court in New York.

"The unusual, if not unlawful activity in his accounts, including one negative net cash balance of approximately $6 billion at the time of Madoff's arrest, was clear evidence that something was seriously amiss."

Picower, 67, of Palm Beach, Florida, was listed 371st and worth $1 billion on the Forbes list published this week.