A federal appeals court said three former Merrill Lynch & Co bankers may be retried on charges they helped Enron Corp defraud shareholders over a sham transaction involving Nigerian power barges.

A jury had in November 2004 convicted bankers Daniel Bayly, James Brown and Robert Furst of conspiracy and fraud charges over Enron's 1999 transfer of the three barges to Merrill.

The Fifth Circuit Court of Appeals overturned this decision in 2006, finding that the government tried the case improperly concerning the defendants' alleged theft of honest services.

But in a June 16 ruling made public on Wednesday, a three-judge panel of the same court said prosecutors may retry the case under other theories without subjecting the defendants to being tried twice for the same crime, or double jeopardy.

These theories include alleged conspiracies to commit wire fraud through the deprivation of Enron's money or property, or to falsify Enron's books and records, the court said.

Our reversal was premised narrowly and solely on the failure of the honest services charge, Senior Judge Thomas Reavley wrote. The opinion implicitly, if not explicitly, recognized the possibility that criminal wrongdoing might be proved in a retrial.

Sidney Powell, a lawyer for Brown, said in an interview she might seek reargument before the entire Fifth Circuit, or appeal to the U.S. Supreme Court.

Brown raised a pure double-jeopardy issue, based on the fact the government is trying to prosecute him again on the same set of facts, scheme and purported offense, she said.

Paul Coggins, a lawyer representing Furst, said the government case still has a ton of legal and factual problems, and that he expects his client to be vindicated.

A lawyer for Bayly did not immediately return a call seeking comment. Justice Department spokeswoman Laura Sweeney declined to comment on a possible retrial. Bill Halldin, a spokesman for Bank of America Corp , which bought Merrill on January 1, declined to comment.

Enron transferred the barges to Merrill when it was under pressure to sell assets to meet a 1999 profit target.

The government called the transfer a sham because Enron agreed to take the barges back in six months and give Merrill a guaranteed return, making it a lease rather than a sale.

It said Merrill agreed to the transfer to curry favor with Enron executives including Andrew Fastow, the chief financial officer. Fastow was sentenced to six years in prison for his role in Enron's collapse.

The case is U.S. v. Brown, U.S. Court of Appeals for the Fifth Circuit (New Orleans), No. 08-20038.

(Reporting by Jonathan Stempel; Additional reporting by James Vicini in Washington; Editing by Brian Moss and Tim Dobbyn)