|Related Characters|| Jo-Beth Casey (Sister)|
Peekaboo Jones (Partner)
|Unlock||Complete the second set of three Story missions|
|Gesture||Jumps up in the air, claps, and then stands with her hands on her hips.|
- Main article: Mansion (Story)
Mary-Beth Casey, alongside Peekaboo Jones, enters the haunted Gallows Hill Mansion to find the remains of a murderer and return them to the gallows.
- Judging by the names and backgrounds of the three Caseys throughout the series, it can be assumed that Jo-Beth Casey in TimeSplitters Future Perfect is the daughter of either Mary-Beth Casey in TimeSplitters, or Mary-Beth's younger sister Jo-Beth Casey (TimeSplitters 2).
- However, despite these assumptions, the creators have confirmed it is the same Jo-Beth in both games and that this time difference was just an oversight on the developers' part.
- Both she and her sister Jo-Beth Casey feature school themed outfits. Mary-Beth wears a cheerleader uniform, and Jo-Beth wears a school girl uniform.
- Her younger sister, Jo-Beth Casey, reuses her voice clips in TimeSplitters 2.
- Ben Newman confirmed that he wanted to put Mary-Beth in TimeSplitters: Future Perfect, but never got around to it.