A known gang leader incarcerated in the Bulloch County Correctional Institute failed a drug test Tuesday and then fought guards who tried to take him to solitary confinement. Marico Carva McCord, 32, of Crimford Court in Lithonia, is serving a prison sentence for burglary and other crimes committed in several counties. After Tuesday's struggle, he was also charged with battery, riot in a penal institution and obstruction, according to Bulloch County Jail records.