CLAYTON, Mo. (AP) – One of the more visible protesters during last year’s unrest in Ferguson has pleaded guilty to starting a fire at a QuikTrip in Berkeley in December.

The St. Louis Post-Dispatch reports (http://bit.ly/1Ho1S9e ) 19-year-old Joshua Williams of north St. Louis County pleaded guilty to arson, burglary and stealing Monday in St. Louis County Circuit Court.

Police say Williams ignited a fire at a QuikTrip in Berkely during protests after the death of 18-year-old Antonio Martin. Martin was fatally shot Dec. 23 by a Berkeley police officer across from the QuikTrip at a Mobil gas station.

Williams was also arrested at least twice during related protests for refusal to disperse and unlawful assembly.

Sentencing for Williams is scheduled for Dec. 10 in St. Louis County Circuit Judge John D. Warner Jr.’s courtroom.