Erin felt Helen's eyes watching her carefully, and she signed off on the file that she was currently working on before looking up into her assistant's face. "What do you need, Helen?"

"You received a letter today."

She frowned, holding out her hand to Helen expectantly. The woman handed over the large manila envelope, and Erin's eyes scanned it carefully, taking note of the fact that her name and the address of the office were scrawled across the paper in that familiar handwriting. "Thank you, Helen. If I need anything else, I'll let you know."

"But!"

Erin fixed a hard look on the woman, knowing that she wanted to know what was in the envelope. "I will be fine opening this in here."

"You don't know that! It could have anthrax inside! If this asshole who's stalking you and replicating cases that the BAU has solved is sticking to pattern, it makes sense that he'd copy a huge one from your past. And that is the Amerithrax case!"

Erin cocked her head to one side as she took a deep breath. "I don't think that this person will go that far. Anthrax is extremely volatile, after all, and there is the likelihood that they might inhale some of the spores themselves."

"And you don't know that for certain. At least let me get you a pair of gloves and a mask to wear before you think about opening it? If you're not going to allow someone else to do so?"

She knew that Helen meant well, but she still felt a little flash of irritation at the woman. "If it will set your mind at ease, I will make that concession."

Helen nodded before fleeing her office, and as soon as Erin was certain she was gone, she pulled out her letter opener and sliced through the seal on the envelope. Just as she was about to open the envelope, a frisson of doubt ran through her system, so she set the envelope aside in order to wait for Helen to return.

"Here, now you can continue."

"How did…?"

"I know you, Erin."

She sighed as Helen laughed a little, and then she was affixing the mask before tugging on the gloves. Then she shooed Helen away, so as not to get any of the powder on her, if there was any inside the envelope to begin with. Sliding out the single sheet of paper, she was relived to find that there was nothing out of the ordinary, no powders to worry about, and she rolled her eyes at her assistant before hurriedly reading through the rambling letter. There was something familiar about the words, something that itched at the back of her brain, and she wondered if Alex would be able to provide any further insight into who she thought wrote the letter. "I'm going to see Agent Blake for a moment, hold any calls that might come in, please."

Helen nodded as Erin got to her feet, the letter in her hand as she left her office and headed for the bullpen. Thankfully, it appeared that Alex wasn't busy when she approached her desk, and Erin tried to relax her face into a small smile, though she knew that it probably looked forced. Clearing her throat to catch Alex's attention, Erin took a seat on the edge of the woman's desk and waited for her to acknowledge her presence. "What can I do for you, Erin?"

"I received another letter today, and this one feels even more familiar than before. Would you please read it and see if you could tell me why I feel that way?"

Alex nodded as she took the piece of paper from Erin's hand and quickly scanned the words on the page. It didn't take her long to reach the end of the letter, and then she was looking up at her, eyes wide and wild. "We need to talk somewhere a little more privately, Erin. Now."

She blanched a little at the strident tone in Alex's voice, giving her a small nod as they got to their feet in unison. "Penelope's office would be the closest office to give us privacy, or I could ask David to spend some time in Aaron's office while we talk."

"Rossi's office might be the better choice, seeing as how you've been trying to keep this quiet up until now." She nodded once more before heading up the stairs to David's office, knowing that Alex would be right behind her. It was clear from her reaction and demeanor that she had a pretty clear idea of who was behind the letters, and Erin knew that it was nothing good for her.

"David, darling, Alex and I need your office for about half an hour or so. Everything's fine, we just need to talk in private about something, and this is the one place where we won't have prying eyes checking in on us. Can you go talk to Aaron about something? Please?"

He gave her a concerned look, but Erin just smiled and shrugged, heading over to his sofa and taking a seat as elegantly as she could. "All right, I'll need to be filled in on what's happening a little later, of course, but for now I'll leave you two alone." David left the office, waggling his fingers at them before he closed the door on them.

Alex took a seat next to her on the sofa and handed the letter back to Erin, her frown deepening as she took a long, deep, breath. "You do know who has been writing you letters. Though I doubt you've thought about him in a very long time."

What remaining color was in her face drained away as she finally connected the dots. "He, he wouldn't do that. He left in anger, vowing never to look back or to think of this place again."

"And don't you think that all changed when I rejoined the team?"

Erin nodded slowly, unconsciously reaching out for Alex's hand. A part of her was still surprised when Alex took hold of it, threading their fingers together as she squeezed softly. "I guess I didn't consider him to be a threat, despite the anger."

"And that means we're in danger." Erin shook her head. "Yes, Erin. He was even more infuriated than I was when we were demoted, and you weren't there to hear the things he wanted to do to you, since he felt you were instigator in our downfall. Over the years, I've started to realise that you were backed into a corner where you had no options, but back then, I agreed with him, saying that you needed to face a comeuppance. So, I think that John might see both of us as traitors now, because I willingly came back to this place, to work with you."

"Which explains why you're getting the letters and items that are exhorting you to bring about my downfall, while I'm getting the creepy, ranty, letters." She sighed deeply. "You do realise that we have no way of proving any of this, though? If we went with the preliminary data to Aaron or David, we would be told that we're making huge leaps in logic and that there needed to be more concrete evidence in order to move forward."

Alex sighed as she nodded, sliding closer to Erin before resting her head against the wall to stare up at the ceiling. "I hate that you're right. I hate that we have to build more evidence against him, especially since we both know how damn smart he is, and how he learned everything that he knows from the same people we did. You have to promise me that you'll not take any risks. I didn't lay down my anger to have you do something stupid and die before we get the chance to properly reconcile."

She chuckled and sobbed all in the same breath, and Alex was leaning over and pulling her into her arms, allowing Erin to cry on her shoulder as she thought about what might be ahead of them, and all that John could possibly do to her family and friends.