PHILADELPHIA (WPVI) -- Investigators in Philadelphia are asking for the public's help in finding the gunman who killed a teenager while she was walking her dog.
It happened just before 9 p.m. Sunday near the 5300 block of Horrocks Street.
New surveillance video shows the shooter waiting two minutes for 17-year-old Teryn Johnson to walk by late Sunday night.
The gunman then shot Johnson in the chest before getting into a waiting Dodge Charger and fleeing the scene.
The teen was rushed to Temple University Hospital where she later died.
Johnson was walking with another teenage girl at the time of the shooting but she was not injured.
A $20,000 reward is being offered for information leading to an arrest and conviction.
Anyone with information is asked to call police at 215-686-TIPS.