When Fabrice Tourre appears before the Senate Tuesday, things are going to get very technical, and sparks are expected to fly. The 31-year-old Goldman Sachs trader, who is the only person named in the SEC’s fraud case against the firm, stands accused of intentionally misleading investors into taking the long positions on a mortgage-backed securities deal. In his prepared testimony, he insists that the transaction "was not designed to fail," because the two investors in question "were two of the most important clients of my desk.” Tourre adds: "I deny—categorically—the SEC's allegation. And I will defend myself in court against this false claim.” Meanwhile, the list of questions Tourre and Goldman Sachs CEO Lloyd Blankfein will face Tuesday is growing longer. Senate investigators claimed Monday that Goldman created a series of intricate deals to squeeze maximum profit out of the home-mortgage crisis that crippled so many of its competitors. (Up until now, the SEC had only pointed to one deal.) “The evidence shows that Goldman repeatedly put its own interests and profits ahead of the interests of its clients,” said Carl Levin, the Michigan Democrat heading the Senate committee. Blankfein is expected to say that Goldman did not consistently short the mortgage market as he tries to explain the firm’s actions.