By Ian Simpson
WASHINGTON (Reuters) - A long-running investigation into the 2010 election campaign of former District of Columbia Mayor Vincent Gray has concluded and no charges will be filed against him, U.S. prosecutors said on Wednesday.
The probe found evidence of more than $3.3 million in illegal contributions in various campaigns between 2006 and 2011, including the 2008 presidential campaign, the U.S. Attorney's Office said in a statement.
"No additional charges are expected to be filed in the investigation related to the federal and local political campaigns," it said.
Although the statement did not mention Gray, a Democrat, he had been a focus of speculation about possible charges involving his 2010 election. Gray, 73, turned down a plea deal in November 2014 that called for him to plead guilty to a felony.
A dozen people have pleaded guilty in the investigation, which began in 2011. They include seven who pleaded guilty to offenses linked to the 2010 election won by Gray.
Gray, who presided over a booming economy and rising population in the U.S. capital, lost the Democratic primary to council member Muriel Bowser in April 2014 as the investigation became an election issue. She went on to win the general election in November.
The most damning claims against Gray were in court filings and hearings that focused on allegations he knew of a $653,000 “shadow campaign” on his behalf funded by businessman Jeffrey Thompson and executed by close associates Jeanne Clarke Harris and Vernon Hawkins.
Gray was also dogged by revelations that a rival candidate, Sulaimon Brown, had been paid secretly by Gray associates to boost Gray’s chances by staying in the race and verbally attacking Democratic incumbent Adrian Fenty.
In a statement, Gray said many people in the District of Columbia and around the United States had had their faith in the justice system tested.
"Justice delayed is justice denied, but I cannot change history. I look forward to getting on with the next chapter of my life, which will no doubt be dedicated to service,” he said.
Prosecutors have asked judges to set sentencing dates for the seven who have pleaded guilty, the U.S. Attorney's statement said.
(Reporting by Ian Simpson; Editing by Andrew Hay and Grant McCool)