Mayoral candidate Vincent Orange waits to speak on Feb. 15 in Washington. (Amanda Voisard/The Washington Post)

D.C. Mayor Vincent C. Gray is the most prominent politician whom prosecutors have named for his involvement at the center of a Washington business executive’s secret scheme to influence local and national politics in recent years.

But the documents released by federal prosecutors Monday show that Gray (D) was just one candidate among more than two dozen whom Jeffrey E. Thompson, a powerful government contractor, sought to help by infusing their campaigns with illegal cash.

With the exception of Gray and former D.C. Council member Michael A. Brown, prosecutors have not publicly identified the other candidates to whom they referred in Thompson’s plea agreement. But people with knowledge of the investigation have confirmed the names of most of those involved.

For example, at Thompson’s plea hearing Monday, Assistant U.S. Attorney Michael Atkinson referred to an at-large council member who “was aware” that Thompson was funding his 2011 campaign, illegally contributing more than $148,000. People familiar with the case have identified the member as Vincent B. Orange (D-At Large), who is now running for mayor. Orange has said that he has turned over campaign records to prosecutors.

After allegations by Thompson were revealed Monday, Orange said he had no knowledge of any “shadow campaign” on his behalf. He did acknowledge that he accepted checks and money orders from Thompson, many of which were probably straw donations.

“If I had knowledge, I’d be indicted,” he said. “I’m not getting indicted. I’m not a co-conspirator.”

In plea documents, Thompson said he “understood” that Orange “was aware” of the secret spending on his behalf. But in court, Thompson acknowledged that he had no direct conversation with Orange and that his presumption of knowledge was through intermediaries.

From 2006 to 2012, according to the plea agreement Thompson signed Monday, the businessman secretly steered more than $2 million to more than two dozen candidates running for the D.C. Council, mayor, Congress and president.

The details of Thompson’s campaign to influence a vast network of candidates were revealed when the businessman pleaded guilty Monday to funneling illegal contributions to federal and local candidates over a six-year period.

U.S. Attorney Ronald C. Machen Jr., at a news conference Monday, said the candidates had “varying degrees of knowledge” of Thompson’s activities.

Gray has dismissed Thompson’s statements as lies.

In the mayor’s case, prosecutors alleged that Thompson hoped that Gray would “expedite” negotiations over a pending settlement with the businessman’s firm, D.C. Chartered Health Plan.

In contrast, prosecutors have not provided details about what Thompson may have been seeking from the other candidates.

According to people with knowledge of the investigation, those candidates included Hillary Rodham Clinton during her 2008 presidential campaign. In his plea agreement, Thompson said he illegally spent $608,750 on canvassers and campaign literature on Clinton’s behalf when she ran against then-Sen. Barack Obama (D-Ill.).

At Monday news conference, Machen did not identify Clinton by name. But he specified that the presidential candidate whom the plea described did not know about the illegal donations.

The federal candidates who also received illegal contributions from Thompson included Del. Eleanor Holmes Norton (D-D.C.); then-Sen. Arlen Specter (Pa.); Sen. Harry M. Reid (D-Nev.), Rep. Charles B. Rangel (D-N.Y.) ; then-Rep. Jesse L. Jackson Jr. (D-Ill.), and Rep. James E. Clyburn (D-S.C.). Those candidates received contributions from Thompson employees Stanley Straughter and Lee Calhoun, who admitted last year to donating Thompson’s money in their own names.

In the District, people with knowledge of the investigation said that Linda Cropp, the former D.C. Council chairwoman who lost in the 2006 mayoral campaign to Adrian M. Fenty, was another recipient of Thompson’s illegal largesse. Prosecutors alleged that Thompson illegally spent $278,000 on Cropp’s behalf without reporting it.

Cropp, in a telephone interview Tuesday, said it was a “big shock and surprise” to see her name associated with Thompson’s scheme. She said she was unaware that his contributions were illegal.

Thompson told prosecutors that he gave Brown $120,000 in illegal donations and spending that was used when he ran for the council in 2007 and 2008. The businessman also told prosecutors that he arranged for $140,000 in illegal spending for Jeff Smith, who challenged council member Jim Graham (D-Ward 1) in 2010.

That year, Thompson also made $26,000 in illegal expenditures to Kelvin Robinson, a council candidate in Ward 6.

Thompson also spent $100,000 on behalf of Mark H. Long, a candidate for an at-large council seat in 2008.

Court documents filed in the Calhoun and Straughter prosecutions indicated that Thompson facilitated illegal donations to seven other local candidates, including Fenty; council members Muriel Bowser (D-Ward 4), David A. Catania (I-At Large), Marion Barry (D-Ward 8) and Yvette M. Alexander (D-Ward 7); and Patrick Mara, a Republican who ran unsuccessfully for an at-large seat last year.

Catania said he was unaware of any illegal contributions from Thompson or any of his surrogates.