Billionaire hedge fund founder Raj Rajaratnam responded forcefully to SEC insider trading charges in papers filed Tuesday by his lawyers at Akin Gump Strauss Hauer & Feld.

In the 32-page response, Akin Gump lawyers claim that wiretaps federal investigators used to implicate Rajaratnam in a $20 million insider trading ring were unconstitutional. They also say the Galleon Group founder was already working with investigators on an inquiry into another hedge fund and that he relied on research analysts, not inside information, to grow his business.