I read the ending was going to be heartbreaking, so I think it might be one of the liars. IMO both Spencer and Toby are very likable characters and are both very good actors, so I think they could probably sell it the best. I think with the history of mental illness in Spencer's biological family it might be possible she has been A the whole time and not known it. To me the most heartbreaking ending would be Spencer finding out it was herself all along and committing suicide. Probably much too dark of an ending though.

Ya and Spencer did have problem with Allison..but so did Hannah. The next episode it says now that they all are convinced who AD is they prepare for a confrontation..so I think we might find out next episode.

I am probably wrong because the writers don't have the guts to do it and it'll probably be some random person but I feel like it's Caleb.

I don't think it will be a random person because it would anger fans. If they made it someone who was not a regular I would be very disappointed. I am kind of hoping for Toby to be AD in a way, because I feel he is the most likable and sympathetic character. I think he is a great actor too, and would like to see him sell and evil side. He also has good reason to want revenge since he was in jail for something the liars did, when they blinded Jenna he got the blame. I think he has the best reason (other than Jenna) to want revenge on the girls.

@tarotdmc said:

I don't think it will be a random person because it would anger fans. If they made it someone who was not a regular I would be very disappointed. I am kind of hoping for Toby to be AD in a way, because I feel he is the most likable and sympathetic character. I think he is a great actor too, and would like to see him sell and evil side. He also has good reason to want revenge since he was in jail for something the liars did, when they blinded Jenna he got the blame. I think he has the best reason (other than Jenna) to want revenge on the girls.

I also think it could be Toby..he has good motive..Caleb was new to the school (as far as we know) he didn't even know Allison..unless they make up some soap opera story where he got a face lift and changed his name. I agree i would be beyond pissed if AD is some random character..i liked the s2 reveal of being mona..cuz even tho she wasn't a main ..we knew her enough to be like omg..but the other 2 reveals..the first one I don't even remember her name (the one that shot Ezra) and then Cece..we barely knew them...especially Cece..she wasn't even in a handful of episodes and for her to be A..blew my mind because (to me) it made no sense.. I think AD is gunna be a male character (if its not one of the liars) cuz all other reveals have been female..(I'm counting Cece as female lol). And if AD is male chances are he had a romantic relationship with Cece. If it's not Toby..then im thinking maybe one of the liars..or the whole spencers twin theory (which i don't think I like very much) Well those are my theories any way..guess we'll find out Tuesday.. I hope we find out who AD is no later then after the first hour (I may need time to process) and not at the very end of the series.

The only thing that makes me question Caleb is cuz he's been a bit shady..like his marriage to hannah..he said cuz they can't testify against each other..did he do that for her? Or for him if he got caught..but if it is him..i have no idea what his backstory would be and how he fits in to it all..as of right now (without that info) it doesn't make sense for Caleb to be AD.

These are shocking ideas. They are certainly plausible but kill any possibility of a happy ending unless a happy ending is just an end to all the madness. Lucas as a childhood friend of Charlotte is still a possibility that leaves the liars' friendship intact.

Ya all I know i hope there are flashbacks on how this whole thing started.

I can see them having Lucas or Caleb be AD. Lucas has motive, and Caleb might have a motive we don't know about. We know he was in foster care, could he be Spencers twin? Maybe he was resentful that Spencer ended up in a wealthy family with a good home while he was in bad foster situations? Caleb also has the technical ability. Ok, scratch that. I just remembered Caleb and Spencer were a couple, but up until then I thought it might work;)