More charges are expected in the government’s broad investigation into possible insider trading at hedge funds.  A source with direct knowledge of the inquiry, who spoke on condition of anonymity, says that cases against as many as 3 people will be brought by the end of the year. Federal prosecutors are focused on traders at Diamondback Capital Management and Level Global Investors, two large hedge funds that were raided by the Federal Bureau of Investigation about a year ago. The investigations into illegal trading at Level Global and Diamondback stem from the government’s inquiry of Primary Global Research, according to a person familiar with the case. Primary Global, which is now defunct, is a so-called expert network firm that connected Wall Street money managers with executives of public companies. Several Primary Global employees and consultants have either been convicted or pleaded guilty to leaking corporate secrets to hedge fund traders. Both Diamondback and Level Global were large clients of Primary Global, according to court filings. At its peak, Level Global, a fund based in Greenwich, Conn., managed about $4 billion. It shut its doors this year after investors requested their money back on the heels of the government’s raid. Diamondback, which has offices in Stamford, Conn., managed about $5 billion at its peak. Traders from the firms have been cooperating with the government’s investigation, potentially leading to more arrests, this person said. One of those aiding the investigation is Spyridon Adondakis, a former junior analyst at Level Global, this person said   The offices of Level Global Investors in Greenwich, Conn., were raided by the Federal Bureau of Investigation in 2010. Mr. Adonkakis could not be reach for comment, but a spokesman for Level Global said the firm fired Mr. Adonkakis in May 2010 for breaching the firm’s confidentiality policies. Spokesmen for Diamondback and Level Global declined to comment on the investigation. Ellen Davis, a spokeswoman for the United States attorney in Manhattan, also declined to comment.  For more info, go to [Dealbook  11/30/11]