The move announced by Karen Floyd was expected, The State reported. But it puts more pressure on the embattled governor.
Sanford, once considered a potential Republican presidential candidate in 2012, revealed in June that he had been visiting his lover in Argentina while his staff said he was hiking the Appalachian Trail alone. He recently announced he has no plans to run for elective office again but said he would serve out his term as governor.
The state Ethics Commission has also been investigating allegations Sanford misused state aircraft. Earlier Thursday, the governor and his lawyer said they had been told the commission would release its report before he defends his conduct before the panel, the newspaper said.
"It is not OK to short-circuit the ethics process to try and get the result you want," Sanford said. "If you go this route you are setting up a kangaroo court."