I haven’t really done research to back this up, but by seeing all the theories, each of the girls have seem to have a reasonable amount of motives to want to get back at the people that hurt them.
As we further progress into the story, this theory that I have leads me more to in all believe truly, that all the girls are Uber A, without the other knowing. Is that why they are called the ‘Pretty Little Liars’? Lets be honest, they all have things to hide, and people to protect, they trust in each other to let each other know some insight about an arising situation, but they don’t tend to spill the whole picture.
Looking back at Mona, she was A but Hannah being her friend, had no idea. Watching season 6B, the intro gives me all the more reason to believe this, because have you noticed that the girls take turns doing the signature “Shhh” during the intro to each new episode?
Notice they aren’t looking at each other, just in different directions, as if, if they were to look at each other, their secrets will be revealed.
Ally is having suspicions, and the picture above she seems to be looking at Hannah, just as she did in the newer episodes, when she prayed about the police discovering Cece’s killer, and later following that prayer, a suspicious yet nasty glare directly at Hannah across the table.
They all seem to at one point, even lose their trust in each other.
So who is in the casket now? Ally isn’t dead…
Or is the casket empty, yet to contain the body of a (PL) Liar?
Two can keep a secret? How about five?
Death seems very customary to them now, doesn’t it?