One of those suspects, 18-year-old Kasheem Williams, was arrested in Philadelphia on Thursday.
A female suspect, 17-year-old Jahme Barnes, remains at large.
Barnes is accused of providing Williams the gun used to shoot a 17-year-old and kill a 25-year-old man on Sunday night.
Police say the suspects and the victims were driving around together in the area of Grant Street and Union Alley.
The bullet reportedly went through the teen's hand and struck the adult in the chest.
Williams and Barnes face charges including third-degree murder and attempted murder.