Is the big bad “A” just somebody’s kid brother?

Tuesday night’s episode of Pretty Little Liars pointed the finger at delinquent lax bro turned grieving boyfriend Mike, who’s acting super shady in the wake of original A Mona’s (Janel Parrish) death.

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So what’s the deal with Aria’s (Lucy Hale) younger sibling? We’ve got the scoop from actor Cody Christian on his character’s mysterious new plot development – and whether he really could be A.

“Well I’m not going to say ‘no.’ I think it’s possible. That’s the thing that keeps the show going: the mystery. You don’t know,” Christian, 19, tells PEOPLE. “Our writers are so amazing at keeping everything unpredictable and keeping everything fresh. I don’t think at this point in the show that anyone is safe from being A.”

(Personally, we kind of love picturing him underneath that blonde wig in the hidden footage of Mona’s brutal slaying.)

But is Christian cheating here? Does he know who A is already, like costar Keegan Allen, who told PEOPLE last week that it’s “so shocking and surprising”?

“No! I’m going to have to give him a call and tell him to spill the beans, because I don’t,” Christian says.

Read on to learn more about Christian’s descent into fan theories and what’s next for Mike.

What is your favorite fan theory out there about who A could be?

Oh, goodness gracious. I couldn’t tell you, I’ve heard so many. I’ve heard that Mike is A, I’ve heard that Aria is A because our dad was A, and then it was like a family generational thing – that he did and then he passed it down to her, and then she’s gonna leave so she’s gonna pass it down to me. I’ve heard some crazy, crazy things. But what does shock me is that the two that I have read that are actually somewhat accurate, I’m like, “Wow, how did you know that?” People are crazy. There are little detectives out there.

Let’s talk about last night’s episode: It was a big one for your character. Should we be suspicious that Mike is on the A Team, and when are we going to figure out why he’s visiting Ali (Sasha Pieterse) in prison?

Yeah, you should be suspicious! I mean, look at his behavior, it’s sketchy as hell. [Laughs] The thing is, Mike is so unpredictable at this point. He’s grieving. I mean, he lost someone that he loved, cared so much about, and I feel like to get those answers of why and what happened, he’s willing to do just about everything. It’s the right choice to be suspicious of Mike at this point. I think that everyone’s red flags should be up. But at the same time, people have to understand that some of his behavior is justified for what he’s been through.

During your Twitter chat last night, a fan asked why Mike doesn’t just tell Aria what’s happening, and you Tweeted back that he may not know who to trust. Why do you think he feels like he can’t confide in his sister?

I feel like Mona’s death was such a shocker and so unexpected. The thing is, I don’t want to give away anything, I don’t know how much he knows or how little he knows, but I feel like he does understand the magnitude of the situation that the Liars are facing. So I think he just has made a decision on his own that he can’t turn to his sister because it will ultimately hurt his sister more than it will hurt him, and I think that he feels he can’t turn to anyone just because of the risk that he poses. So I think Mike’s going to stick to himself and try to figure it out on his own, which is the wrong thing to do. I really wish he would find somebody to confide in, but he’s going to do what he feels best.

I want to float a theory by you based on last night’s episode: We saw in a flashback that Mona wished she could stop time to shoplift and break into people’s houses to spy on them. That reminded me of your character earlier on in the show, when he had his breaking-and-entering phase. Is there a chance they bonded over this and she involved him involved in her schemes to stop A?

That’s the interesting thing, that’s a very good question. Mike and Mona were not your average, typical boyfriend-girlfriend. So now, the real question is: How much does Mike know about Mona and her past and her plans and her secrets? And I feel like the answer to that question is going to be explained and really opened up in the next couple episodes.

What can you tease about next week’s episode?

It’s going to be a big one, I’ll tell you that, it’s gonna be a big one. It’s the first time Mike is shirtless in five seasons, so I think that’s something to be hyped about. I actually put a lot of work into that, so I hope it goes over well. Yeah, I think that next week the fans are going to see a much darker side to Mike that’s going to raise much more suspicion, and we’re going to be asking so many questions. I mean, you just want to know what’s going on with the character and why he’s doing the things that he’s doing. But, ultimately, we will get the answers by the finale, and we’re going to see how all of his behaviors are justified – or not justified, for that matter.

I also saw that your Tweeted Hanna’s (Ashley Benson) sass was sexy while confronting Holbrook. Did you know that in the books, Hanna and Mike end up together? Would you be down for that on the show?

Well first I want to say that I know I misspelled “Hanna” – I put an “h” at the end. [Laughs] But I do want to also say that I was extremely sick yesterday, like I was blowing my nose every 20 seconds, but I didn’t want to miss the live Tweets, so I did what I had to do. But I do know that they are together in the books. Do I see that making its way into the series? Eh, I don’t know. And I’ve touched on this before, I just feel like our fans have had so much time to fall in love with the relationships on the show that it would be quite difficult to get them to change their path and direction and accept a new relationship, and I think we’re going to see that and kind of see how fans respond to that with the Talia (Miranda Rae Mayo) and Emily (Shay Mitchell) thing. There are a lot of fans of Paige (Lindsey Shaw) and Emily, so now it’s going to be interesting to see how people either reject or accept this new relationship. And I think maybe that could be a test to say, “Well, is our audience ready to accept another type of relationship on the show,” but we’ll see.

On the bridge, Mike told Aria that he isn’t going to be controlled by anyone anymore. Was he talking about Ali? Or maybe his dynamic with Mona?

I think Mike has always allowed other people to call the shots. He’s seen where that has led, and he’s seen what has happened. Maybe the shots being called led to Mona’s death. Who knows? I think at this point he’s just tired of feeling like a kid, and he’s going to go out there and he’s going to get the answers he wants to get. He’s going to say, “Stop treating me like a little boy, I’m a man. I’m going to do what I want to do and I’m going to handle it the best way I know how.”