A key cooperating witness in the U.S. government's probe of insider trading was a technology analyst named Karl Motey who made dozens of calls to gather evidence for the government, the Wall Street Journal reported on Monday, citing a person familiar with the case.

Motey was known only as CW-2 in the complaint that led to the arrest on Thursday of three technology company executives, the WSJ reported, citing the person.

Motey, who runs a Los Altos, California-based research firm called Coda Group Inc, did not return several calls for a comment, the newspaper said.

The analyst was a business contact of a partner of Richard Choo-Beng Lee, people familiar with the matter told the Wall Street Journal. Lee has helped authorities since he pleaded guilty in the insider-trading prosecution of Galleon Group hedge fund founder Raj Rajaratnam and 22 others last year.

A spokesman for the Federal Bureau of Investigation in New York and a spokesman for the Manhattan U.S. attorney's office did not immediately respond to a message seeking a comment.

Lawyers believe last week's arrests were just the start of a series of arrests by federal prosecutors over the next few months.

(Reporting by Elinor Comlay, Editing by Maureen Bavdek)

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