The last and perhaps most scandalous chapter of Troopergate has yet to be written.

While the demise of Eliot Spitzer cleared the way for vigorous fact-finding on the part of Albany County district attorney David Soares, who released his corrective report of the affair only after the governor was obliterated from office, a key question remains unsolved.

It’s an important one because it concerns the conduct of the executive director of the Public Integrity Commission, Herbert Teitelbaum, who enforces New York’s ethics and lobbying laws and whose office has been conducting its own investigation of Troopergate for the better part of a year.

What led Mr. Teitelbaum to launch a perjury investigation of Mr. Spitzer’s communications director, Darren Dopp?

In October, after Mr. Dopp testified before him, Mr. Teitelbaum evidently concluded that he had committed perjury and asked Mr. Soares to investigate. At that point, Mr. Teitelbaum halted his investigation for several months.

The basis for the referral was Mr. Teitelbaum’s belief that Mr. Dopp in his testimony had contradicted an earlier statement that he had submitted to Attorney General Cuomo’s office in which he expressed regret for any “appearance of impropriety” that resulted in his pursuit of Mr. Bruno’s travel records.

In his interview with Mr. Teitelbaum, Mr. Dopp was defiant, asserting that he had no regrets and that he had done nothing improper. He maintained that he was following orders from above. This was the reed on which the perjury case hung.

Let’s look at the context here. The only high-level aide to be punished by Mr. Spitzer, Mr. Dopp had already lost his job and now faced the possibility of misdemeanor charges.

On the line was not simply Mr. Dopp’s livelihood but also his credibility. What would it matter what he had to say about what Mr. Spitzer knew about the effort to discredit Mr. Bruno if he was a convicted perjurer?

As we now know from Mr. Soares’s report, Mr. Dopp had damaging information about the governor. He knew that Mr. Spitzer had not told the truth when he told district attorney investigators that he did not direct the release of Mr. Bruno’s travel records.

Mr. Dopp, in fact, in late June had laid out all flight manifests and travel assignments before Mr. Spitzer, who directed him to give them to the Times Union.

The assumption has been that Mr. Dopp concealed his knowledge of the governor’s involvement until Mr. Soares granted him immunity during his second investigation of the matter.

I give odds that that assumption isn’t true. I believe that Mr. Dopp, during eight hours of questioning, told Mr. Teitelbaum in October that he wasn’t a lone gunman but that he took the Bruno records to Mr. Spitzer, and the governor ordered him to hand them over to the Times Union. I believe that Mr. Teitelbaum was told that Mr. Spitzer had lied.

My hunch would help to explain why Mr. Dopp found himself battling to stay out of prison just days after he testified before the public integrity commission. And it would also raise the troubling question about what Mr. Teitelbaum did with Mr. Dopp’s testimony. Did he forward it to the district attorney or did he sit on it?

Mr. Teitelbaum, who took up his job as the state’s top ethics enforcer after a respected career as a class-action litigator, cannot answer these questions because state law forbids him from discussing aspects of the case in the public.

His message to me is: Don’t judge until I’m done.

“Until we produced a product … people can put all kinds of spin on what they’re doing. But it’s the product that speaks volumes,” he said. “What I say about an investigation is really not the best evidence. It’s the thoroughness of the work, the balance of the work that tells a story.”

He adds: “Government can become a rumor-mill, and I’m not going to respond to all of the rumors that come out about the commission or about me.”

And he leaves me with a tantalizing suggestion that there may be more to the story than we know. “Nobody really knows what we’re looking at,” he said.

That may be the case, but I still can’t think of a credible explanation for halting the investigation and going after Mr. Dopp that doesn’t raise questions about the motive of the referral to Mr. Soares.

Mr. Dopp has emerged as the fall guy in the scandal. The Spitzer administration assumed that by punishing him and expunging him from the statehouse, they could contain the damage and persuade investigators to back off.

Did the integrity commission protect Mr. Spitzer at the expense of Mr. Dopp? The answer, I presume, will be in the transcripts of Mr. Dopp’s testimony to Mr. Teitelbaum. Unfortunately, the testimony may never see the light of day.

jacob@nysun.com