You're in the shower and your boyfriend of several months, Spencer, is sitting on your bed when he drops his phone on your carpeted floor. As he leans over to pick it up, he sees a manila envelope tucked up in the underside of your bedframe. Morbid curiosity gets the better of him, and he grabs the envelope. He looks at your bathroom door, discerns that you'll still be at least a few more minutes in the shower, and then opens the envelope.
As he flips through its contents, his stomach sinks. Inside are detailed notes, in your handwriting, describing murders from a case he's been working on, paired with photos of the crime scenes that have never been released. Things he's never told you, things you couldn't possibly know... unless you're the unsub he and his team have been looking for. Spencer hears the shower turn off, but he's too shocked to move, confusion whirring through his mind. A few minutes later, you emerge from the bathroom, dressed and drying your hair with your towel, and he looks at you with an expression that's a cross between surprise and betrayal.
"What the hell is this?" he asks, his voice barely above a whisper. You glance down at what he's holding, and feel your heart skip a beat at the thrill that he's discovered your secret. You've kept this from him for months, and finally decided to toy with him a little. You're a psychopath, and you've killed multiple people since engaging in a relationship with Spencer. He's never even suspected that you could be capable of something like this, and you decided it would be exciting to set yourself up and try to convince him that you've been framed.
"What's what?" you reply, your brow furrowing as you try to get a look at the papers spread out on your bed. Your eyes widen in practiced surprise as you see notes that eerily mimic your handwriting, though you've intentionally changed some strokes and pressure points so you can claim a forgery.
"Y-you..." Spencer stammers, his voice laced with hurt. "You're the killer."