Investigators say the 16-year-old was walking to the bus stop at Nelson Street and Peach Street - that's near Effingham Street and Jefferson Avenue.
They say she noticed the man behind her and started walking faster; and so did he.
Officers say the teen ran back to her home and the man took off.
A little later, police say they found the man and charged him with assault.
The suspect has been identified as 58-year-old David L. Liggins of the 1900 block of Prentis Avenue in Portsmouth.
Police say this incident is not connected to last week's abduction case.
Stay with NewsChannel 3 for updates as they become available.