An attorney for Sen. John Ensign (R) said Tuesday that the Senate Ethics Committee’s decision to hire a special counsel to lead its investigation of the Nevada lawmaker “does not change the course of its inquiry,” and said Ensign will continue to cooperate with the panel.

The Ethics Committee announced Tuesday that attorney Carol Elder Bruce, a partner at the law firm K&L Gates, will serve as special counsel in the “preliminary investigation” focused on Ensign.

The committee did not specify the allegations, but Ensign has faced allegations that he tried to cover up an affair with the spouse of his former top aide. Ensign first acknowledged the affair with Cynthia Hampton, a campaign staff member married to administrative assistant Doug Hampton, in June 2009.

“The Senate Ethics Committee has assured Senator Ensign that their inquiry remains in the preliminary stage and that the appointment of a special counsel does not change the course of its inquiry,” attorney Rob Walker said in a statement Tuesday. Walker, an attorney with Wiley Rein, has previously served as the chief counsel of both the Senate Ethics Committee and the House Ethics Committee.

“Senator Ensign is confident that he complied with all ethics rules and laws, and he is hopeful that this appointment will lead to a more speedy resolution of this matter. As Senator Ensign’s office has been doing, they will continue to cooperate with the Committee’s inquiry,” Walker said.

Both the Justice Department and the Federal Election Commission declined in late 2010 to pursue the allegation against Ensign.

Chairwoman Barbara Boxer (D-Calif.) first confirmed in October 2009 that the committee had begun to investigate Ensign. But in a statement with Vice Chairman Johnny Isakson (R-Ga.) issued Tuesday, she said the inquiry remains in its preliminary stage.

“The purpose of a preliminary inquiry is to determine whether there is substantial credible evidence that a violation within the Committee’s jurisdiction has occurred,” Boxer and Isakson said in a statement.

The statement continued: “The possible responses after a preliminary inquiry are dismissal of the allegations, a letter of admonition, or, for more serious violations, an adjudicatory review. An adjudicatory review generally involves more formal proceedings, including notice to the Senator of the nature of the possible violations, a description of the evidence of such violations, and the right to a hearing before the Committee recommends disciplinary or other action.”