Sen. Robert Torricelli will not face criminal charges for campaign finance wrongdoings, U.S. Attorney Mary Jo White announced Thursday.

White's office said she reached her decision after "an exhaustive investigation by her office and agents of the FBI, IRS, and US Custom Service." 

"I am satisfied that after a thorough investigation, Ms. White and her office have appropriately exercised their prosecutorial discretion, in keeping with the Department's longstanding guidelines," said Deputy Attorney General Larry D. Thompson in a written statement.

The Department of Justice is referring information it found in the course of its investigation to the Senate Ethics Committee for any action it may choose to take.

On Thursday, Torricelli expressed relief that the saga was over.

"I spent every day trying to be as good a Senator as I could be, but this was a lengthy and personally painful experience. I plan to put this entire matter behind me and I intend to redouble my efforts on your behalf," he said in a written statement.

The New Jersey Democrat had been facing charges of campaign finance violations for taking gifts and illegal cash donations from a contributor. Businessman David Chang pled guilty last year to making $53,700 in illegal donations to Torricelli's 1996 Senate campaign. 

Chang told prosecutors that the senator accepted gifts in return for intervening in Chang's business deals in North and South Korea. He agreed last year to work with investigators, but Torricelli's attorneys dismissed Chang's claims as "delusional."

Torricelli repeatedly denied any anything illegal in his five-year relationship with Chang. 

White indicated in November that the tide may turn for Torricelli, whose political future seemed shaky following a possible indictment. The break bodes well for first-term Torricelli's re-election, particularly as Republicans have not yet fielded a top rank challenger for the November elections.

White was expected to leave her post at the Justice Department on Jan. 1, but has yet to do so.

The Associated Press contributed to this report.