US federal prosecutors examining the case of the Galleon Group have widened their investigations, and have sent a subpoena to a former employee of SAC Capital Advisors, according to the Wall Street Journal, quoting unnamed sources.

The subpoena is asking for trading records from Richard Grodin, a former SAC hedge fund manager who employed a cooperating witness in the insider trading case announced last week, the newspaper said.

Mr Grodin left SAC in January 2004.

The report said the the subpoena does not suggest wrongdoing. Neither Galleon nor Mr Grodin could be reached for comment, the report said.

The investment industry has been digesting news of criminal charges that were last week brought against Galleon founder Raj Rajaratnam and five others in the largest hedge fund insider trading case on record.