In the episode "She's Come Undone", it was revealed that CeCe witnessed a fight between Spencer Hastings and Alison DiLaurentis the night of Ali's disappearance and that Jessica DiLaurentis paid CeCe to be quiet about it.
That CeCe witnessed a fight between Spencer Hastings and that Jessica DiLaurentis paid CeCe to be quiet about it. This was what it was revealed in the episode "She's Come Undone". That CeCe witnessed Alison DiLaurentis the night of Ali's disappearance and that Jessica DiLaurentis paid CeCe to be quiet about it. This was what it was revealed in the episode "She's Come Undone".