FBI and Senate Ethics Committee investigators have obtained the e-mails, copies of which were provided to The New York Times by someone the newspaper said was involved in the case. The investigation began following disclosure that Ensign had conducted a sexual relationship with Cynthia Hampton, whose husband, Doug Hampton, had worked as an aide in Ensign's office.
The Times reported in October that Ensign helped Doug Hampton get lobbying work and then assisted Hampton's clients in dealings with government agencies. Ensign has said any actions he took on behalf of Hampton's clients were not done at Hampton's request.
The newly disclosed e-mails indicate Ensign suggested that a Las Vegas development company hire Doug Hampton, after the company had sought Ensign's help on a number of projects in 2008, the Times reported Wednesday.
"Senator Ensign has stated clearly, he has not violated any law or Senate ethics rule," Ensign spokeswoman Rebecca Fisher said. "If Doug Hampton violated federal law or rules, Senator Ensign did not advise him to do so, did not suggest that he do so, and did not cooperate with his doing so."
FBI and Senate spokesmen had no comment, the newspaper said.