(Corrects to show in first two paragraphs Nguyen worked at research firm, not expert network firm)
By Basil Katz
NEW YORK, June 26 (Reuters) - U.S. law enforcement authorities said on Tuesday they arrested and charged an executive at an in vestment research firm as part of the government's wide-ranging probe of insider trading at the now-defunct Galleon Group hedge fund.
Tai Nguyen of research firm Insight Research LLC surrendered to the FBI Tuesday morning, an FBI spokesman said, and was expected to appear in federal court in Manhattan later in the day.
Nguyen was facing charges related to insider trading, the FBI said, but the exact charges have not yet been made public.
Lawyers for Nguyen and the firm could not be identified immediately.
The FBI and federal prosecutors in Manhattan have mounted a campaign to root out insider trading on Wall Street, focusing in part on employees at so-called expert network firms who they say helped funnel corporate secrets from consultants at companies to hedge funds.
The FBI said Nguyen was charged as part of its investigation of wrongdoing at billionaire Raj Rajaratnam's Galleon fund.
Rajaratnam was convicted of 14 counts of securities fraud and conspiracy last year and is serving an 11-year prison term.
His case led to the conviction this month of former Goldman Sachs Group Inc board member Rajat Gupta for feeding secret company tips to Rajaratnam.
Also, federal prosecutors said Adam Smith, a former Galleon employee turned government cooperator, will be sentenced later Tuesday before U.S. District Judge Jed Rakoff in Manhattan, who oversaw the Gupta trial. (Reporting By Basil Katz; editing by Jeffrey Benkoe)