The Senate Ethics Committee investigation into Sen. Larry Craig (R-Idaho) continues to lurch forward, despite the fact that none of the key players — besides Craig — have been contacted.

But as in past Ethics probes, the committee could rely for its investigation on Craig’s guilty plea and other public records in the Minnesota legal proceeding in which Craig is attempting to retract that plea. Despite initially stating his intention to resign, Craig has now vowed to remain in the Senate until January 2009.

Regardless, it may be a long time before the secretive panel’s findings are made public as Senate Ethics rules dictate a long and largely opaque process.

According to those rules, a preliminary inquiry can last for as long as the chairman and ranking member of the committee desire and the committee’s progress may not be made public until the case is dismissed, a letter of admonition is issued or a broader inquiry is opened.

Kathleen Bangs, the public affairs manager for the Minneapolis-St. Paul International Airport, said no one on the airport’s staff — nor prosecutor Christopher Renz — has yet been contacted by the Ethics Committee.

Bangs said “there had not been a single inquiry” about the June 11 incident in the airport’s men’s room, where Craig was arrested by an undercover police officer for allegedly soliciting gay sex.

But Natalie Ravitz, a spokeswoman for Ethics Chairwoman Barbara Boxer (D-Calif.), indicated last week that the probe is still under way.

“The Ethics Committee is continuing to conduct its preliminary inquiry,” Ravitz said.

Sen. John Cornyn (R-Texas), the committee’s ranking member, would not comment.

Craig told Roll Call that he did not know the status of the Congressional investigation, but confirmed that he had indeed been contacted by the Ethics Committee.

But the committee may be relying on already public documents and testimony in the Senator’s appeal of his guilty plea currently taking place in a Minnesota courtroom.

In its July 30, 2002, letter of admonishment to then-Sen. Robert Torricelli (D-N.J.), the committee relied heavily on documents obtained in the federal investigation into Torricelli’s relationship with campaign donor David Chang.

“The Committee notes that the record of the Department of Justice investigation made available to the Committee, consisting of thousands of pages of information, disclosed an investigation which was sweeping in scope, exceedingly detailed and thorough, and obviously the product of substantial investment of government resources,” the letter read.

“The quality of this record renders unnecessary any attempt by this Committee to duplicate the Department of Justice investigation,” the letter added.

Although the public record in the Craig investigation is not nearly as extensive, it could become the basis for a determination of whether Craig violated Senate rules.

On Aug. 29, Senate Minority Leader Mitch McConnell (R-Ky.) and four other GOP Senate leaders filed a complaint with the Ethics Committee that sparked a preliminary inquiry into Craig’s behavior.

Since then, some experts have questioned whether the Ethics Committee is the proper venue to investigate Craig as the incident in the Minnesota restroom appears unrelated to official Senate business.

Even if the committee does have jurisdiction, it may be a long time before its findings are made public.

According to the Senate Ethics Manual, which lays out the committee’s rules for proceeding, the preliminary inquiry may be of “such duration, scope and conduct as may be deemed appropriate” by the panel’s chairman and ranking member.

A preliminary inquiry may include “inquiries, interviews, sworn statements or subpoenas deemed appropriate” to make a judgment about whether to move on to a full inquiry. The respondent — in this case, Craig — may be allowed a chance to respond to the charges and “periodic confidential status reports” could be made to the full committee, which consists of three Democrats and three Republicans.

At the conclusion of the preliminary inquiry, ethics proceedings dictate that a confidential oral or written report be presented to the full committee.

The full committee then determines whether “substantial credible evidence” of an ethics violation has occurred. The committee can dismiss the allegations at this point, or issue a letter of admonition, which would be provided to the complainant (McConnell) and the respondent (Craig). That letter likely would make its way into the public sphere.

If “substantial credible evidence” of an ethics violation is found, four of the six committee members could at that point vote to open a broader inquiry known as an “adjudicatory review.” That vote is not required to be made public, but by nature adjudicatory reviews are more visible as they are likely to include public hearings and witnesses.

Only when the adjudicatory review is finished is a public vote required on the committee’s findings and disciplinary recommendations, which could include expulsion, censure or a fine.

Erin P. Billings contributed to this report.