Senate Ethics Committee investigators have been in Nevada in recent days interviewing businessmen about Republican Sen. John Ensign's efforts to raise political contributions from them while urging them to hire particular lobbyists.
The senator's legal problems revolve around whether Ensign helped a former aide, Doug Hampton, violate a one-year lobbying ban.
Hampton left Ensign's staff after Ensign had an affair with his wife, Cynthia. Ensign helped Hampton land work with the lobbying firm.
Ensign also is under criminal investigation by the Justice Department's public integrity section.
It has become clear that investigators in both the criminal and ethics probes are also delving into Ensign's role in trying to raise money during a period in 2008 when he ran the National Republican Senatorial Committee.
Yost reported from Washington.
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