(Bloomberg News) Noah Freeman and Donald Longueuil, former junior portfolio managers at SAC Capital Advisors LP, according to a person familiar with the matter, were among four hedge fund employees charged in a U.S. crackdown on insider trading.

Longueuil, who worked at SAC Capital unit CR Intrinsic from July 2008 to July 2010, was arrested this morning. Freeman, who worked at SAC Capital from June 2008 to January 2010, pleaded guilty yesterday as part of a cooperation agreement with prosecutors. The person who identified their work history declined to be identified because it isn't yet public.

The two others charged by federal prosecutors in Manhattan were Samir Barai, the founder of Barai Capital Management, who surrendered to authorities this morning, and Jason Pflaum, who worked for Barai and pleaded guilty yesterday as part of a cooperation deal.

The arrests in what prosecutors called a four-year scheme signal an expansion of a 16-month attack on insider trading on Wall Street that U.S. Attorney Preet Bharara said is "rampant." A criminal complaint refers to at least six hedge funds, which it doesn't name, that employed the defendants or executed trades.

"They took the concept of social networking and turned it into a criminal enterprise," Bharara said at a press conference detailing today's charges.

Primary Global

The arrests are connected to earlier arrests of eight employees or consultants at Primary Global LLC, a Mountain View, California-based firm that links investors with employees of public companies who work as consultants. Barai got inside tips from Primary Global consultants Anthony Longoria and Winifred Jiau, both of whom were previously charged, today's complaint says.

Barai and Longueuil were both charged with conspiracy to commit securities and wire fraud, three counts of securities fraud and separate counts of obstruction, and are set to appear today in Manhattan federal court. The U.S. said the conspiracy operated from 2006 to 2010.

In the criminal complaint against Freeman, the U.S. said that in October 2009, while Freeman was at "Hedge Fund B," he had a telephone conversation with a co-conspirator. The complaint doesn't identify the fund. The date coincides with Freeman's time at Stamford, Connecticut-based SAC.

Steven A. Cohen, chairman and founder of SAC Capital Advisors, didn't immediately return an e-mail seeking comment.

SEC Case

The U.S. Securities and Exchange Commission today sued Barai, Pflaum, Freeman, Longueuil and Barai Capital in what it called a $30 million insider-trading scheme.

Before joining CR Intrinsic, Longueuil worked at Empire Capital and was an investment manager focusing on the media, technology, telecom and energy industries at Morgan Stanley, according to a posting on Spoke.com, a professional networking website.

Before working at Morgan Stanley, he was a research analyst for Longueuil & Co., working directly as an outsourced researcher for hedge funds and other investment professionals, according to Spoke.com.

Freeman was a managing director at Sonar Capital Management LLC in Boston from March 2005 to May 2008, according to data compiled by Bloomberg. Neil Druker, founder of Sonar Capital, didn't immediately return phone messages. Freeman also has worked as an analyst for Brookside Capital, according to LinkedIn, a professional social networking site.

In a Dec. 29 complaint against Jiau, the U.S. said two portfolio managers at different firms, whom it didn't identify, conspired with Jiau, 43.

Pflaum, who pleaded guilty yesterday to conspiracy and securities fraud, worked as a research analyst for Barai and obtained material nonpublic information for him to benefit the unnamed hedge fund, the U.S. said in court papers. Pflaum has been cooperating with the U.S., prosecutors in Bharara's office said in court papers.