Another investigator for the agency that conducts security background checks for 90 percent of federal employees has pleaded guilty to falsifying reports. Thomas S. Fitzgerald, 48, a former special agent for the U.S. Office of Personnel Management, is the seventh background investigator to be convicted since 2008 for falsifying security clearances, prosecutors said.

Fitzgerald, of Crofton, could face up to 18 months in prison under federal sentencing guidelines, prosecutors said.