The court-appointed trustee of Bernard Madoff's investment firm, given the responsibility of recovering billions lost by the victims, has sued JP Morgan for $6.4bn (£4.1bn) claiming the bank played a central role in the fraud.
A lawsuit filed in New York by Irving Picard accused JPMorgan, Madoff's "primary banker", of aiding and abetting the fraud.
"JPMorgan was willfully blind to the fraud, even after learning about numerous red flags surrounding Madoff," David J Sheehan, counsel to Picard, said in a statement.
"While many financial institutions enabled Madoff's fraud, JPMorgan was at the very centre of that fraud and thoroughly complicit in it," the statement added.
Picard said his suit seeks $1bn in fees and $5.4bn in damages.
The trustee has so far recovered about $1.5bn for Madoff creditors.
Any money recovered from JPMorgan will be returned to Madoff's victims on a pro rata basis, the trustee said.
JPMorgan has claimed that it did not know about or in any way assist in the fraud orchestrated by Bernard Madoff.
The bank said it has assisted Picard in his investigation of Madoff's firm and called his claims "irresponsible and over-reaching."