When Alex (Laura Prepon) and Piper (Taylor Schilling) first reconnect at the beginning of Season 3, Alex certainly doesn’t seem suspicious. The first thing Piper does is ask why Alex is back, and Alex can barely even answer her. She tells Piper how embarrassed she is that she ended up back in prison, and she clearly blames herself for what happened. At one point, she even tells Piper she thinks she’s having a nervous breakdown. After a fight with a guard nearly lands her in solitary confinement in 3x02, Alex breaks down and asks, “How am I back here, Piper? How could I have let myself get back here?” One of the recurring points of the show is how unhealthy the relationship between Alex and Piper is, and the audience, knowing what Alex may or may not, has to wonder how exactly Alex got herself back into the pattern of their very co-dependent relationship.  

Piper tries to comfort a hysterical Alex through a bathroom stall.

 

Later in 3x02, Red (Kate Mulgrew) confronts Piper for lying to her about the fate of her restaurant. When Piper tells Alex she thought lying would make Red feel better, Alex agrees, saying, “Delusion can be very comforting.” The whole conversation after that, in which they discuss how much happier Piper was when she thought someone besides Alex had turned her in to the police, has a subtext of Alex knowing more than she’s letting on. After Piper says, “Ignorance was bliss,” the two of them exchange a knowing glance, and Alex looks almost angry. Alex retorts that coming clean to each other about everything they’ve done would be much better for both of them. “So much better than ignorance.” Whether intentionally or not, she practically goads Piper’s confession right out of her. 

Alex learns that Piper is the reason she’s back in prison.

 

When Piper finally does come clean to her, Alex hardly seems surprised. She’s upset, and she’s furious with Piper, but she’s not surprised. Maybe that’s because she’s had her suspicions all along but didn’t want to believe them, or maybe it’s just because she knows Piper and knows this is the kind of stunt she would pull. Either way, the idea that Piper would get her sent back to prison doesn’t surprise her, so even if it was only on a subconscious level, Alex probably had an inkling of what was going on but didn’t want to act on it or even believe it.