The State Law Enforcement Division says 49-year-old Gerald M. Evans of Bishopville has been charged with threatening the life of a public official.
State police say Evans sent a handwritten letter to the then-governor in October threatening Sanford and his family. Authorities did not release details of the letter.
Evans began serving a 30-year sentence for armed robbery in 1994. He is not eligible for parole.
Sanford left office in January.