A Savannah man faces a minimum of 87 years in prison if convicted of a series of armed robberies of convenience stores in which a co-defendant has already pleaded guilty.

Garnell Dewitt Quarterman, 30, of Savannah made his first appearance in federal court Monday after a federal grand jury charged him with 23 counts of armed robbery.

Quarterman is charged with 12 armed robberies or attempted armed robberies from Nov. 9, 2019, through Jan. 6, 2020, throughout metro Savannah.

Quarterman’s co-defendant, Malic Stephens, 26, of Savannah pleaded guilty on Nov. 9, 2020, to one robbery count. He has yet to be sentenced.

Police arrested Quarterman at a residence Jan. 17; Stephens was arrested Jan. 23 at his residence.