Requested by user35309251: Could you do an imagine of Peter and Y/N in a criminal minds AU?

*Please note: For those of you who don't know, "Criminal minds" is basically a show about a team who solves murders (very sorry if I offend any fans by explaining it so basically, I haven't seen it in a long time lmao). With that being said, this one-shot contains themes of murder and dead bodies, and so whilst it is NOT graphic, please be mindful of that before you read if you feel that those themes will trigger you. Thank you and enjoy :)*

I got out of the car, my gaze looking up at the massive building as I shut the car door. I walked up the steps to the Manor House and showed the police officer at the door my badge and ID. He gave me a nod before lifting the police tape and allowing me in. I immediately grimaced as I walked in, blood splatter up all of the walls as I walked in. Investigators buzzed around the scene, the forensics working on getting photos and collecting any possible evidence from the murder that had taken place. I walked in, my face scrunching up further as the woman lay dead on the floor, several wounds littering her body as her eyes remained open. I sighed and shook my head. I'd been doing this job for five years now, and I still grimaced at the gruesome ways that people died. I looked up and gave MJ a small smile as she walked towards me.

"You okay, MJ?" I asked as we hugged.

"Better than this woman. Son found her dead at seven this morning, but didn't call it in until half seven." She nodded. I narrowed my eyes and looked at her.

"Why the delay? If I found my mom's clearly murdered dead body, I'd be ringing the police immediately." I stated.

"Exactly. Some of my guys are interviewing him now as to why he waited, but he doesn't seem to have a good reason. Needless to say that he's currently our main suspect." She replied.

"Cause of death?" I asked.

"That's Peter's area, not mine." She teased, making me playfully roll my eyes at her.

"Apparent cause of death?" I retorted.

"Gunshot to the head. Though, there was clearly a struggle. She's got knife wounds all over her body, as well as whatever Pete will uncover at the autopsy. We don't have a motive yet." She sighed. I returned it and bit my lip as I looked around the scene.

"Well, keep working. I'll see what Peter has to say once he's looked over the body. Keep me in the loop." I nodded.

"Same goes for you." She responded. I gave her another small smile and bumped her fist with mine before leaving the scene.

I walked into Peter's lab, my heels clicking against the floor as I walked in.

"Hey, Pete-." I was stopped in my tracks and was forced to come to a stop as suddenly a web pinned my wrist to the door. I rolled my eyes and looked ahead at Peter, who was standing there with his wrist extended and his finger on the trigger of his web shooter.

"How many fucking times, Pete?" I scoffed and shook my head.

"It's because you don't knock, you could be anyone for all I know." He chuckled as he tossed me a vial of the dissolve fluid.

"We're best friends and work colleagues, I don't have to knock." I teased back, making Peter playfully roll his eyes as I poured the fluid into the web, dissolving it instantly and freeing myself.

"Anyway, I've done the autopsy on your murder victim. And let's just say that I found some interesting stuff." He stated as we headed to stand around the table that the body was laid out on. My eyebrows furrowed at him.

"Go on." I nodded. He sighed and looked down at the body.

"So, at first, of course I thought that the gunshot wound to the head was the cause of death. But then I cut her open, and her liver was absolutely destroyed." He admitted as he glanced back at me. My eyebrows furrowed more.

"Destroyed by what?" I questioned.

"A poison called Saracotin. It's extremely slow acting, depending on the dosage, it can take weeks to kill whoever is being given it. But the trademark of the poison is that the liver ends up wrecked. Just like this one is." he nodded. I bit my lip, my mind starting to work as I looked at the body.

"Is it safe to assume that the killer shot her in the head to try and cover up the fact that the real cause of death was poison?" I asked. Peter shrugged and nodded as he looked at me.

"Unless someone was poisoning her, and another person actually killed her, yeah. It's safe to say that your theory is more than likely correct." he replied. I bit my lip and squinted my eyes as I remembered something that MJ had said.

"What is it, Y/N?" Peter asked. I looked at him.

"MJ said that their main suspect so far is the woman's son, because he claims that he found her dead at seven, but waited for half an hour to call the cops, and he can't give a good reason for the delay." I shook my head.

"He doesn't work with anything like this, does he? Because only toxin specialists and forensics would know that Saracotin does this to the body. I would be shocked if the killer knew about their poisons but still chose to use one that so obviously points to that as the method of murder." Peter scoffed.

"He's an electrician. So, no. He wouldn't have known. Everything points to him." I stated.

"I think that it's time to pay him a visit." Peter stated, making me nod as he grabbed his jacket.

Peter and I got out of the car, a sigh leaving my lips as I looked up at the son's house and shut the car door.

"This is it, Pete. Be vigilant." I mumbled. He nodded and clenched his jaw as he also looked up at the tall structure.

"I'll go around the back, see if there's a way in." he spoke. I returned his nod as he disappeared around the side of the house and I headed up the steps to the front door. I gently knocked my fist against the wood, but nothing could be heard from the other side of the door.

"Hello, Mr Carver, are you there? I just want to ask you some questions about your mom's murder!" I called out. I sighed and bit my lip as I still heard nothing. I raised my fist to the door again.

"Mr Carver-." As soon as my fist touched the door again, it slowly creaked open. My eyes widened slightly, my heart starting to pound as it swung open slowly. I sighed and bit my lip as I pulled my gun out of its holster.

"This is exactly how people in horror movies die." I mumbled to myself as I raised my gun and slowly walked into the house. I gulped and looked around carefully, my hands pointing my gun at anything that moved as I wandered through the seemingly abandoned house.

"Mr Carver?! We just want to talk." I shook my head. I looked down the hallway as Peter appeared there, his gun also out.

"Anything?" I whispered. He shook his head, making me sigh.

"You check upstairs. I'll stay down here." I nodded, making him return it. He crept up the stairs, his gun aimed up them as I headed into what seemed to be the living room. I looked around and sighed as I couldn't see anything outwardly suspicious. Not that there would be anything, especially if he was actually the murderer. I looked to the desk and my eyebrows furrowed as a box sat on it, the lid slightly ajar and allowing the sun to bounce off of whatever the contents was. I walked towards it and removed the lid completely, more questions filling my brain as I looked at the small vial of liquid. I leant down and brushed the dust off of the label. My eyes widened, my breath hitching as I read the label. My eyes flicked over the letters that spelt out 'Saracotin', making my heart stop.

"Peter!" Suddenly, a knife was put to my throat, making my eyes widen further.

"Nice and slowly, Detective Y/L/N, or your partner will have to do an autopsy on you too." Carver spat into my ear, making me clench my jaw and slowly raise my hands.

"Why did you do it? She was your mother, for Christ's sake." I snapped.

"That bitch never did anything for me. I was with a nanny until I was old enough to be shipped off to boarding school, and then I was there until I was eighteen. The only good thing that she ever did for me was die so that I could cash in on her life insurance. All I did was push that forward." he smirked against my ear, making me grimace.

"You murdered her, simply because she wasn't a present mom. Insurance money or not, what you did was fucked up, you murdered her." I spat.

"Step away from Detective Y/L/N, or I'll shoot." Carver whipped around, making me cry out as he turned me around with him. I gulped, my hands holding Carver's arm that was around my neck as Peter stood at the doorway, gun aimed at my captor.

"This doesn't have to end in a second body, Carver. You've done enough damage already. Just let her go." Peter nodded as he started to slowly walk towards us.

"I have to kill her too. I can't get caught, I can't." he shook his head.

"You're caught anyway. Killing her won't change that." Peter shook his head, making me gulp as his eyes started to get glassy.

"No. This is the only way." Carver choked before starting to slice my neck.

"NO!" Peter yelled before raising his other wrist and firing a web at the knife. Carver's eyes widened as Peter swished the web, allowing me to run out of the man's arms as the knife was flung across the room. I ran to Peter, his arm protectively pulling me into his body as we looked at Carver. The man looked at us desperately before turning to run.

"I don't think so." Peter scoffed before firing another web at his back. He yanked, making him cry out as he was pulled to the floor and knocked unconscious. I breathed a deep sigh of relief, Peter returning it as he took his face into my hands.

"Fuck, are you okay?" he gulped as I raised my hand to the small wound on my neck that Carver had managed to cut.

"It hurts, but I'm okay. Thank you for saving me." I sighed as I hugged him tightly.

"I wasn't about to watch you die." he chuckled into my hair, making me smile and bite my lip as I looked up at him before flicking my eyes to Carver.

"Another murder solved, I think that it's safe to say." Peter nodded. I returned it and sighed before looking back at him.

"What a great team we make." I smiled, making him smirk and nod as I tightly hugged him again.