Defense lawyers for a hedge fund billionaire charged with insider trading accused the government Monday of “gaming the system” by failing to advise the judge who approved the wiretaps that much of the evidence had been gathered in ways that made the electronic surveillance unnecessary. A lawyer for Galleon Group founder Raj Rajaratnam told a New York federal judge that during a yearlong joint investigation, the SEC and federal prosecutors had built a “conventional” insider trading case using “conventional” techniques.

A unanimous federal appeals panel has overturned an order requiring defendants in the sprawling Galleon securities fraud case to hand over to the SEC roughly 18,000 wiretapped conversations they had been given by prosecutors in a parallel criminal prosecution.

A judge’s order that defendants in a civil insider trading case turn over to the Securities and Exchange Commission wiretaps they obtained in discovery in their criminal case came under fire Thursday at the 2nd Circuit. A lawyer for Raj Rajaratnam and Danielle Chiesi, central figures in a wide-ranging insider trading prosecution that has already netted 11 guilty pleas, asked a three-judge panel to reverse New York federal Judge Jed Rakoff’s February order compelling production of the wiretaps.