A USIS background investigator has pleaded guilty to charges stemming from falsifying a report. The charge could carry a penalty of five years in prison. In addition, The Justice Department has accused USIS, the government’s largest contractor for providing background investigations, of shortcutting more than 665,000 background checks for more than four years beginning in 2008. But it’s far from the first time a lone security-clearance investigator has faced tough penalties for falsifying background investigations. Since 2008, the Office of Personnel Management (OPM) has been on a crusade to root out falsification in background investigations using the courts.