A fraudster who diverted half a million dollars from a bank account belonging to the law firm Boies, Schiller & Flexner has sparked a lawsuit between two major banks.

In January 2011, a person who called himself Devrin Anderson contacted Mike Robertson, the founder of InstaPayPlan, a company that facilitates bank-to-bank transactions between jewelry sellers and buyers. Anderson claimed he was a lawyer from Boies Schiller and told Robertson that his firm was helping to liquidate a client’s jewelry estate and needed assistance in transferring the funds from one of the firm’s Wells Fargo & Co. accounts to a JPMorgan Chase & Co. account.

Robertson verified the Boies Schiller account numbers that Anderson gave to him. Anderson made five transactions amounting to $495,000.

A few days after the transfers, Boies Schiller notified Wells Fargo that it didn’t authorize the transactions and that it didn’t employ anyone named Devrin Anderson. The bank also canceled a sixth scheduled transfer amounting to $110,045.

Wells Fargo requested that JPMorgan provide it with a copy of the transfer agreement between InstaPayPlan and Anderson. Although the agreement did have Boies Schiller’s account number, it didn’t include other required information and had been signed by someone who didn’t work at the law firm. Wells Fargo now is suing JPMorgan because it is refusing to reverse the transactions or credit Wells Fargo for the loss.

In a statement, Boies Schiller, the firm of famed litigator David Boies, said that it is “an innocent bystander” in the dispute and has been “fully reimbursed for these fraudulent transactions.”

Read Thomson Reuters for more information about the suit.