Why? Oh, lots of reasons, not the least of which being that we don't trust any Rosewood newcomer. But here are the top seven things that really ring warning bells for us.
1. She was tight with Alison. And, honestly, anyone who Alison (Sasha Pieterse) gets close with is a bit suspect. Did they bond over their scheming ways? It's very possible, especially because everything about CeCe's mannerisms is reminiscent of Ali.
2. Ali never told the Liars about her. If they were so close, why did Ali keep CeCe a secret? Did something dark happen between them?
3. She knows the Liars' secrets. There's a major power imbalance between CeCe and the Liars, and she loves to hold it over them. Not exactly the actions of a friend.
5. The way she handled the Nate/Jenna (Tammin Sursok) situation. She steamrolled over Emily's (Shay Mitchell) protests, and had no problems imitating an angry girlfriend on the phone. If she can come up with a lie that quickly and pretend to be someone else that easily, what else is she hiding?
6. She knew Noel Kahn's (Brant Daugherty) brother. Eric Kahn was tight with members of the NAT club. Any connection to him is suspicious.