(CNN) - South Carolina's Attorney General has decided that Gov. Mark Sanford will not face criminal charges following an investigation into his travel and campaign expenses.
"After conducting a thorough investigation, the evidence does not support beyond a reasonable doubt that the governor knowingly, willfully, and intentionally set out to break state law, which is the criminal prosecutorial standard that must be reached," Attorney General Henry McMaster said Monday at a press conference in Columbia.
For the last five months, McMaster had been reviewing the results of a state ethics investigation into Sanford's use of state planes and campaign funds - a probe that started after media organizations began examining the governor's financial practices following his disclosure of an extramarital affair last June.
That investigation resulted in 37 ethics charges against the Republican governor, whose term expires in January. Sanford resolved the civil charges in March by paying $74,000 in fines.
But on Monday, McMaster said the ethics violations did not rise to the level of criminal conduct. The law, he argued, "requires a much higher standard before criminal prosecution is warranted."
"A criminal prosecution is not appropriate under these circumstances and we do not believe a criminal conviction could be obtained," McMaster added.
Sanford thanked the Attorney General and the ethics investigators for their "deliberate approach and work" in recent months. He said McMaster's decision reaffirms his belief that the Sanford administration has always "been a stalwart defender of the taxpayer. "