It felt good to finally close that case— for everyone but Spencer.
The team had been working their most recent case (strings of murders in the D.C. area) on and off for a few weeks now, and then finally, just two weeks ago, they caught you. And you fit the profile, with little to no holes. You were the perfect suspect, and though you kept denying that you did it, they assumed that your pride was getting in the way of admitting your loss. The murders stopped once you were convicted, after all. It must've been you.
But something about you, about this case, has been nagging at Spencer. The rest of the team is completely convinced that you're the killer, but Spencer can't be so sure. He has no physical evidence to prove his theory, just... intuition. But it sounds stupid putting it that way, so he keeps it to himself. It certainly keeps him up at night, however, trying to figure out why the hell he doesn't believe that you did it.
Today, after eating in the prison cafeteria, a guard comes up to you. "You have a visitor," he says, which confuses you. You can't think of a single person who'd want to visit you. Everyone in your life believes you're a killer. You follow him to the visiting room, and when you look through the window to see who it is, you just get even more confused. One of the agents who locked you up. Spencer Reid. Looking nervous to say the least, with his fidgeting hands and mussed hair, as if he had run his hands through it repeatedly. The door buzzes and unlocks to allow you in and he perks up to meet your eyes.
"This is definitely not allowed," you say to him. There's no way an agent can visit a prisoner without it being an interrogation, but if this were an interrogation, you'd be in a different room. He opens his mouth to speak, maybe to argue or defend himself, but soon he closes it again and averts his eyes. So you are right. This is against protocol. So why is he here?