NBC10 has obtained exclusive surveillance video showing a SEPTA Police officer nabbing a robber. It happened at the 30th and Market Street station around 9 a.m. Thursday. Investigators say the robber tried to steal a cell phone from a University of Pennsylvania student. That's when authorities say plain clothes Sgt. Tim Catto sprang into action and subdued the 14 year-old suspect. During a struggle a man stepped in to help Catto. The teen was taken into custody. His accomplice ran off.