NEW YORK (CNN/Money) - The New York state attorney general issued a subpoena to Salomon Smith Barney requesting copies of all documents authored by the firm's top telecom analyst, Jack Grubman, widening the probe into possible conflicts of interest among Wall Street analysts, a newspaper reported Thursday.

The subpoena requests the release of all communication between Grubman's research team and the firm's banking group as well as any information pertaining to how Grubman's team was paid, according to a Salomon document dated April 11, the New York Times said.

Attorney General Eliot Spitzer requested documents dating back to January 1998 related to 54 telecommunications companies, all but one of which Grubman wrote reports on, the Times said.

In his investigation of possible conflicts between companies that pay firms for financial services and whose analysts also have recommended their stock to investors, Spitzer is focusing on those instances where investors have lost large sums of money after taking analysts' advice.