John “Swipe” Derrickson, 27, of Chester, Pennsylvania, was shot in the back of the head with a .38-caliber handgun and killed near Second and Grace Streets on July 26, 1991. Memorial information and a contemporaneous newspaper account identify the death as gun violence that led to criminal prosecution.

Sean Artwell, a Chester man, pleaded guilty to third-degree murder in connection with Derrickson’s killing. At sentencing Artwell, then 21, reportedly showed little outward emotion. Assistant District Attorney Heather Mattes sought a sentence of ten to twenty years; the judge imposed nine to eighteen years. Victims’ relatives spoke in court about the emotional impact, and Artwell apologized and asked for another chance; family members on both sides addressed the court.

Artwell is the only named person tied to Derrickson’s death and no other suspects or arrests are identified. If anyone knew John Derrickson or has information about the case, please share what can help the record.