By Nate Raymond NEW YORK (Reuters) - A trial starting this week will provide a window into what prosecutors have called a decade-long insider trading scheme at Steven A. Cohen's once-powerful SAC Capital Advisors hedge fund. Michael Steinberg, a top portfolio manager at SAC, faces charges he illegally traded in technology stocks. His trial, set to start on Tuesday, comes just two weeks after Cohen's firm agreed to pay a record $1.2 billion to settle insider trading charges. Steinberg, who is on leave from SAC, became the highest-level employee at Cohen's firm to face criminal charges after he was arrested at his home on New York's Park Avenue on Good Friday this year. A verdict for prosecutors in New York would continue their winning streak at trial in a broad crackdown on insider trading on Wall Street. Since the first charges were announced in October 2009, 76 people have been convicted. Barry Berke, Steinberg's lawyer, declined to comment on the case, but in the past has said his client did "absolutely nothing wrong" and his "trading decisions were based on detailed analysis." While several SAC employees have been charged, most have pleaded guilty. Steinberg is the first to fight his case before a jury. Another SAC manager, Mathew Martoma, is set to follow to trial in January. Both cases are expected to highlight not just the conduct of the individual traders but also the extent SAC Capital's culture and compliance failures encouraged insider trading. SAC, once a $14 billion hedge fund, agreed November 4 to cease acting as an investment adviser as part of a plea deal. A federal judge is weighing whether to accept SAC's subsequent guilty plea to fraud charges. "CIRCLE OF FRIENDS" In the trial of Steinberg, 41, the prosecution's case is expected to turn in part on the testimony of a star witness, Jon Horvath, who has been cooperating with prosecutors since pleading guilty in September 2012, on the eve of his own trial. Prosecutors have said Horvath, an SAC analyst, was part of a "corrupt circle of friends" who swapped inside information for the benefit of their hedge fund employers. The case focuses on trades involving the stocks of Dell Inc and Nvidia Corp in late 2007 through 2009 at Sigma Capital Management, an SAC hedge fund focused on technology stocks that Steinberg oversaw. In the case of Dell, prosecutors say that in 2008 and 2009, Horvath received non-public information in advance of Dell's quarterly earnings announcements from Jesse Tortora, an analyst at Diamondback Capital Management. Tortora, in turn, got his information from another analyst, Sandeep Goyal at Neuberger Berman, prosecutors say. Goyal got his information from Rob Ray, an employee in the investor relations department at Dell, where he previously worked, according to the charges and testimony in a previous trial. Among the trades outlined by prosecutors is one made in advance of Dell's earnings report on August 28, 2008. After receiving a tip, Tortora talked on the phone with Horvath on August 18. Four minutes after that call ended, Horvath called Steinberg. A minute after that call ended, Sigma began shorting Dell shares. In an email to Steinberg after the call, Horvath asked to "keep the DELL stuff especially on the down low" and said Tortora "asked me specifically to be extra sensitive with the info," according to the indictment. The bet, along with a further short sale on Dell's stock made on August 28, allowed Sigma to earn about $1 million, the indictment said. Both Tortora and Goyal pleaded guilty to conspiracy to commit securities fraud and securities fraud charges in 2011 and are cooperating with the investigation. Ray was not charged. Tortora is expected to be the second witness called at Steinberg's trial, prosecutor Antonia Apps said at a hearing Thursday. NVIDIA TRADES The Nvidia trades also resulted from information that passed through many hands before reaching Steinberg, prosecutors have said. It started with Chris Choi, who worked in Nvidia's finance unit, who gave details about the company's financial results to Hyung Lim, a family and church friend, according to court records and testimony in the earlier trial. Lim then circulated details on to Danny Kuo, a manager at Whittier Trust Co, who in turn provided the information to Horvath, prosecutors say. Horvath then told Steinberg, the indictment said. The information provided insight into the fact that Nvidia's gross margins were lower than expected. Prosecutors say that as a result of the tip, Steinberg sold off Sigma's entire Nvidia position, earning over $400,000. Lim and Kuo pleaded guilty to insider trading charges in 2012. Choi was not charged. Prosecutors have said they also intend to introduce evidence of other trades Steinberg made in Dell and Nvidia in 2008 and 2009. They have received a judge's permission to demonstrate how Steinberg's trading patterns mirrored those of other hedge fund managers who similarly received Dell and Nvidia tips from Horvath's circle of analysts. Among those managers were Todd Newman, a former portfolio manager at Diamondback Capital Management, and Anthony Chiasson, a co-founder of Level Global Investors. Trades in Dell and Nvidia figured in their trial, and a jury convicted them in December 2012. Newman was sentenced to 4-1/2 years in prison and Chiasson to 6-1/2 years. They are out on bail pending appeal. Jury selection in Steinberg's trial is set for Tuesday. Trial before U.S. District Judge Richard Sullivan, the same judge who oversaw the trials of Newman and Chiasson, is expected to last up to four weeks. The case is USA v. Steinberg, U.S. District Court, Southern District of New York, No. 12-cr-00121. (Reporting by Nate Raymond; Editing by Leslie Adler)