I began a November 2012 column on this page with this question: “Which candidate accepted an off-the-books, five-figure payment in exchange for dropping out of a race for a D.C. political office?” [“When city hall is stuck in greed’s grip,” Nov. 17, 2012].

The answer appeared this week in a Statement of Offenses signed by former government contractor Jeffrey E. Thompson. The description of criminal conduct, also signed by Thompson’s attorney and a federal prosecutor, was filed in federal court Monday in connection with Thompson’s guilty pleas to federal and D.C. offenses.

It states in part:

“In September 2006, when it appeared to Thompson that [Michael] Brown would not win the election but would take away from mayoral candidate B [Linda W. Cropp], Thompson met with Brown to encourage Brown to drop out of the race. As a result of those discussions, on or about September 6, 2006, Thompson and Brown agreed that Thompson would pay Brown $200,000, and would enter into a consulting agreement with a lobbying firm that employed Brown, in return for Brown dropping out of the race for Mayor of the District of Columbia and endorsing [Cropp].

“On or about September 7, 2006, Brown publicly announced a suspension of his campaign and endorsed [Cropp].

“On or about September 8, 2006, Thompson authorized a payment in the amount of $200,000 to be made for the intended benefit of Brown. Thompson, on behalf of TCBA [an accounting firm founded, owned and chaired by Thompson], and Brown, on behalf of a lobbying firm that employed him, also executed a 12-month consulting agreement in which TCBA agreed to pay a retainer of $12,500 per month for a total of $150,000.”

I recount this episode to underscore the ominous statement U.S. Attorney Ronald C. Machen Jr. made in a news conference Monday afternoon after Thompson’s plea hearing. “What you learned about today,” Machen declared, “is only the tip of the iceberg.”

Accounts of unethical or illegal activity in the District, such as the rumored candidate I cited 17 months ago (though the deal was richer than I wrote), have been circulating since the federal investigation into D.C. corruption launched more than three years ago. Some of those stories have been tracked down and reported. But much of what’s known has yet to surface officially.

A clue, however, might be found in the final sentence of Thompson’s court document. “This statement of the offense,” the prosecutors wrote, “is not intended to constitute a complete recitation of all facts known by Thompson, but is, instead, intended to provide the necessary legal basis for the guilty plea.”

In other words, the government is holding something back.

Those who think that, with Thompson’s guilty plea, the worst is over should revise their thinking.

Yes, Thompson’s money corrupted many federal and city elections. But he couldn’t have pulled it off alone. To make his schemes work, Thompson needed people willing to help him get around the law.

Thompson got employees, friends, business associates and others to make political contributions in their own names, concealing that the money came from him. He later paid them from his own pocket or from corporate funds. Those helpers are described as “conduits” in court documents.

We aren’t talking about a handful of enablers. In a document filed in court, the prosecution said that between roughly about September 2006 and April 2011, “Thompson utilized at least 75 conduits to make contributions to at least 15 mayoral and D.C. Council candidates in excess of at least $500,000.” And that’s not counting additional hundreds of thousands of dollars that Thompson funneled into “shadow” campaigns.

If those 75 individuals were knowing participants — they expected their campaign contributions to be reimbursed — then they should be held accountable, too. Call them small fry? I don’t. They conspired with Thompson to win campaigns by cheating.

If people can be aggressively pursued and fined for traffic violations or for overdue library books, why not for abusing elections — the process by which leaders are chosen?

Conduits are part of the government’s unfinished business.

So, too, are Mayor Vincent Gray and the campaign committees of other candidates cited in the statement of offenses.

Prosecutors and Thompson said Monday that Gray knew about the off-the-books financial scheme to help him win the 2010 election. Gray, who is seeking the Democratic nomination in the April 1 primary, denies the charge and is fighting it in the court of public opinion.

A war of words won’t do. A court of law is better.

The question is simple: Was Gray part of a conspiracy to funnel unreported money into his 2010 campaign?

One way to find out: Charge him and let a judge and jury decide. Gray’s attorney Robert Bennett told me Friday: “I’m ready to go to trial tomorrow. I have investigated the hell out of this case.” Because of the election, “If Gray is charged, I’m going to ask the judge to start the trial within a month, so Vince can clear his good name.”

Prosecutors should pursue any other candidate — public official or otherwise — who knowingly accepted from Thompson’s excessive and unreported campaign contributions. They have fouled the system.

That iceberg’s time has come.

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