A teenager accused of capital murder in a fatal December 2019 shooting has pleaded guilty to the lesser charage of 1st Degree Murder. Seventeen-year-old Antonio Grigsby, Jr of Texarkana was then sentenced to life in prison. Grigsby was only 15 when he shot 18-year-old Amilleon Jackson five times in the back in the parking lot of a Texarkana apartment complex. Jury selection had been scheduled for yesterday.