Brendan McDermid / REUTERS Former SAC Capital employee Mathew Martoma exits the Manhattan Federal court following an appearance on insider trading charges in New York November 26, 2012.

When the FBI showed up at Mathew Martoma’s multimillion-dollar Florida mansion shortly before dawn on a November morning in 2011, the former SAC Capital hedge fund trader fainted on his front lawn. Federal agents had arrived to inform Martoma that U.S. prosecutors had evidence that he had violated federal securities laws. Now, Martoma is set to go on trial in the Southern District of New York for what the federal government calls the largest insider trading crime in U.S. history.

Martoma, 39, is accused of orchestrating a $276 million financial scheme while working as a trader for SAC Capital, the multibillion-dollar hedge fund built by reclusive Wall Street billlionaire Steven A. Cohen. Martoma is charged with trading illegally on inside information he obtained from a doctor involved in a 2008 pharmaceutical trial for an Alzheimer’s drug that was being jointly developed by Elan Corp. and Wyeth. For more than a year, Martoma, who has pleaded not guilty, has been free on $5 million bail.

Martoma has been charged with one count of conspiracy to commit securities fraud and two counts of securities fraud. Each fraud count carries up to 20 years in prison. “As a result of the blatant corruption of both the drug research and securities markets alleged, the hedge fund made profits and avoided losses of a staggering $276 million, and Martoma himself walked away with a $9 million bonus for his efforts,” Manhattan U.S. Attorney Preet Bharara said when the charges were announced, adding that the alleged insider trading occurred “on a scale that has no historical precedent.”

Martoma’s prosecution is part of a larger, multi-year federal investigation into SAC Capital. Last year, SAC was charged with securities and wire fraud for a decade-long scheme in which the fund engaged in a pattern of “systematic insider trading” that allowed it to reap hundreds of millions of dollars in illegal profits. Federal prosecutors said Cohen’s firm displayed “an institutional indifference” to unlawful conduct that “resulted in insider trading that was substantial, pervasive and on a scale without known precedent in the hedge fund industry.”

(MORE: SAC Capital Indicted, in a Blow to Billionaire Steven A. Cohen)

Last November, SAC agreed to settle the case by paying $1.8 billion and pleading guilty to fraud charges. Cohen, as sole owner of the firm, paid the entire amount. It was the largest insider trading fine in U.S. history. As part of the deal, SAC also agreed to shut down its investment advisory business, which means that SAC Capital is essentially defunct, except as a vehicle to manage Cohen’s still-considerable wealth. Federal prosecutors have tried to convince Martoma to cooperate in their ongoing investigation into Cohen, but the former trader has refused.

Cohen is a legendary Wall Street figure who amassed a $9 billion fortune while building a reputation as one of the most successful hedge fund traders of his generation. For years, SAC Capital consistently delivered astounding returns of 30% or more to its clients. In doing so, Cohen amassed a fortune that enabled him to purchase a 35,000 square-foot Connecticut mansion filled with hundreds of million of dollars worth of art. Among other high profile pieces, Cohen keeps a giant yellow Jeff Koons balloon dog sculpture on his lawn.

But how much of Cohen’s financial success was due to insider trading? That remains an open question. On Wall Street, rumors of insider trading at SAC have persisted for years, as veteran Wall Street reporter Charles Gasparino tells FRONTLINE’s Martin Smith in a new documentary airing Tuesday night.“If you walked up to a typical Wall Street trader and said: ‘Is there insider trading at SAC Capital going on?’ After the guy falls on the floor dying of laughter, he’ll get up and say ‘yes,'” Gasparino told Smith. “It’s a naive question. That’s their reputation.”

In the high-stakes world of billion-dollar Wall Street hedge funds, traders are constantly on the lookout for “an edge” — that little piece of information that might yield an advantage over the competition and generate profits. The U.S. government alleges that SAC Capital’s insider trading scheme lasted from 1999 to 2010, a period of time in which a “relentless pursuit of an information ‘edge’ fostered a business culture within SAC in which there was no meaningful commitment to ensure that such ‘edge’ came from legitimate research and not inside information.”

(MORE: U.S. Regulators File Charges Against Hedge Fund Billionaire Steve Cohen)

Cohen has never been charged criminally in the case — and has maintained that he acted appropriately at all times — but he does face civil charges alleging that he failed to supervise two of his employees who have been accused of insider trading. The Securities and Exchange Commission alleges that Cohen received “highly suspicious” information that should have caused any “reasonable” hedge fund manager to investigate the basis for trades made by Martoma and another former SAC portfolio manager, Michael Steinberg, who was also charged with insider trading.

The SEC alleges that Cohen ignored “red flags” and allowed Martoma and Steinberg to place the suspicious trades. Last month, a federal jury convicted Steinberg on several criminal charges related to insider trading. As the jury entered the courtroom, Steinberg fainted. The former SAC trader faces decades in prison, but will likely only serve a few years behind bars. He has been released on bail and is scheduled to be sentenced in April.

Steinberg’s conviction was another victory for Bharara, the crusading U.S. Attorney for the Southern District of New York who has made insider trading his signature law enforcement mission. Over the last several years, Bharara has secured no less than 77 insider trading convictions — and hasn’t lost a single case. Several other former SAC employees have cooperated with the government and pleaded guilty to insider trading charges. (In 2012, TIME featured Bharara in a cover story and later named him to the TIME 100.)

On Wall Street, Bharara’s pursuit of Cohen has been compared to Captain Ahab’s quest to vanquish the White Whale. Bharara’s investigation into insider trading in the hedge-fund industry has already led to the convictions of former Galleon Group founder Raj Rajaratnam and former Goldman Sachs director and McKinsey managing director Rajat Gupta. Rajaratnam is currently serving an 11-year prison sentence, and last year Gupta was sentenced to two years in prison. Bharara says the U.S. Wall Street insider trading investigation is ongoing.