Rep. Charles Wilson (D-Tex.), once a member of the House committee investigating drug use on Capitol Hill, is under investigation by federal officials for allegedly using cocaine, according to sources familiar with the inquiry.

The sources said that a federal grand jury has heard allegations made by one House staff aide, who himself is under investigation, that Wilson 49, a six-term member from a rural East Texas district, obtained cocaine on several occasions for his own use. Federal officials are investigating those same allegations to determine whether there is enough evidence to seek an indictment.

NBC News last night quoted Wilson as saying that he had been to parties where cocaine had been used, but denied using it himself.

Wilson's press aide, Elaine Lang, told The Washington Post last night that Wilson was in transit from Texas to Washington. She said she knew "absolutely nothing" of the allegations. "He doesn't even smoke cigarettes," Lang said, adding that it seemed "pretty silly" that someone would accuse Wilson of using cocaine.

During the last Congress, Wilson served on the House Committee on Standards of Official Conduct, known as the House ethics committee, which is conducting the House's investigation into possible drug use on Capitol Hill. The committee's investigation was triggered by a federal investigation into allegations of drug use by House members and aides.

Wilson is the second member of Congress whose name has surfaced in connection with the federal investigation. Former Republican Rep. Barry Goldwater Jr. of California was secretly taped by federal agents investigating allegations of drug use. A spokesman for Goldwater has denied that Goldwater did anything wrong.

Two Washington men whose arrest last April launched the federal and congressional investigations were indicted last November on charges of running a cocaine distribution ring. They are believed to be in Australia and federal authorities are working with Australian officials to return them to the United States.

The U.S. Attorney's office, at the request of top officials in the Justice Department, decided last summer to break a longstanding policy of not investigating drug users and agreed to make an exception because the allegations concerned public officials.

Sources said yesterday that, although the investigation is continuing, the department has not officially decided whether to seek charges against officials who have been accused of recreational use of either cocaine or marijuana.