A/N: Thanks for all the reviews and alerts! Here's chapter 13 :)

Disclaimer: I do not own NCIS or any original characters!

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Tony stood at the end of the hallway in the dark with his gun ready. He listened around the corner and heard movement in the living room. Someone was slowly creeping toward the hallway. He took a deep breath and quickly rounded the corner with his gun pointed ahead of him and turned on the light switch in one movement.

"NCIS," he announced himself, but when the light turned on and he focused his eyes on the person in front of him, he was shocked. "Marie? What are you doing?"

"You weren't supposed to wake up," Marie muttered. Tony looked down at Marie's hand and noticed the knife she was holding.

"Put down your weapon," Tony instructed.

"No," Marie said sternly.

"Marie, put it down," he repeated.

"No!" Marie exclaimed. "Not until I set things right."

"What are you talking about?" Tony asked, still pointing his weapon straight at her and not breaking eye contact. He could see fury raging in her eyes.

"I knew you were getting to close to figuring it out," Marie began. "But I thought after I sent you after my neighbor, you'd lay off of us."

"Us?" Tony repeated her word. Had he been right? Was Marie involved in the killing of her husband after all?

"Yes, us," Marie replied. "You were getting way to close to figuring it out. I was sure that after you let me go that day, you would realize you'd hit a dead end...That or you'd arrest that oaf who lives next to me."

"Arrest him for what? He was guilty of nothing," Tony said. "You killed your husband, didn't you?" A satisfied smile crossed Marie's face as she began to chuckle.

"Of course I did," she replied. "I'm the one who pulled the knife across his throat, not Crystal. And after you let me go free that day, I decided I had to put an end to everything before you actually found out the truth. We planned out the most effective solution...surely NCIS would be so blinded with grief that they'd just forget all about who killed John Davis." Tony glanced down at the knife in Marie's hand and realized exactly what she meant by that.

"You wanted to kill us?" he asked. This sparked a maniacal flash in Marie's eyes.

"You two were the ones that kept pushing so hard to figure it out. You were always who I talked to...I knew you never stopped suspecting me. It had to end," Marie explained. Tony couldn't believe it...this woman actually broke into his and Ziva's apartment to kill them to try and prevent NCIS from finding out the truth. Tony then showed a look of confusion as a question crossed his mind.

"How did you know where we live?" he asked. Marie smiled, obviously proud of her tactics and eager to share them.

"After I was let go that day, I noticed you and your wife were leaving too. I told my friend who picked me up to follow you. She kept asking why, but I refused to tell her. I just told her it was important and she did what I said. We followed you all around town, and I'll be honest, had I known you were going house shopping I would have chosen a different day. But at every stop you made, I was there. Finally, you drove here, and I knew this was it," Marie explained. Tony thought back to Ziva saying she had been seeing the same car. It was Marie.

"So then what about Crystal?" he asked. "She had to have been involved. She gave herself up today."

"Oh, she was involved," Marie admitted. "But not in the way you people keep assuming."

"What do you mean?" Tony asked.

"You keep trying to make me believe that my husband and Crystal were having an affair," Marie began. "I've told you several times, that's not true. And it's really not."

"Then why don't you explain it to me," Tony said. Marie let out a chuckle, and she brushed her hair off of her face.

"Well, she didn't lie about having sex with John," she started. "Crystal and I had met a couple of times because John and Shawn knew each other, so for John's birthday, I thought I'd let him have every man's dream. I ran the idea past Crystal, and she was all for it. John was thrilled, but what man wouldn't be?"

"You're saying Crystal had a threesome with you and your husband?" Tony asked for clarity when Marie stopped talking.

"That's exactly what I'm saying," Marie replied with a giant smile. "That was the only time she ever hooked up with John. So, yes, you were right. She did cheat on her husband with John...once. But there's something else you were right about. Crystal was having an affair, but not with him." The room fell silent as Tony registered what he was being told.

"You?" he asked. Marie nodded.

"That's right, Agent DiNozzo," she said. "The night of John's birthday, Crystal and I fell in love. There was just something there...I'd never been with a woman before. So we started seeing each other regularly. We planned on leaving our husbands, but when I tried talking to John about it, he went insane. He wouldn't accept it, and he kept calling me awful names and trying to forbid me from seeing Crystal anymore."

"So you killed him?" Tony guessed.

"Well not just like that," Marie replied. "I didn't want to kill him. I wanted to give him a chance to accept Crystal and I...He wouldn't. I needed out of the marriage, but a divorce would have taken too long, and if I moved out, I couldn't have supported myself. So, Crystal and I waited for him to get home one night. When we saw him coming up the sidewalk, we went outside. Crystal grabbed his arms and held them behind his back. I'm surprised he didn't fight her off...probably because she's a woman...He was always a gentleman like that. Then, I slit his throat. He was begging me not to, saying he loved me, but I didn't care. I didn't want him. We wrapped his neck in a towel and tossed the knife. Then we shoved him in Crystal's trunk and took him to the pond. Took the towel back and dropped him in the water. I thought we disposed of everything. But you just had to keep pushing."

"Yeah, that's our job," Tony said sternly. "And you're sick. If you want out of a marriage, you can get out. You don't have to kill someone."

"I had to do what was best for me and Crystal," Marie said. "Getting rid of John was best."

"And you thought you could get away with murdering someone?" Tony asked.

"I almost did. I would have if you would have left us alone. But when Crystal texted me telling me you were at her house to get her again, I knew we had reached the end of the line. And now, she's locked up," Marie said with venom in her words.

"Yes she is. And after that detailed confession, you'll be joining her real soon," Tony said.

"Oh no I won't," Marie replied, her eyes glistening maniacally. "But I made a vow that I'd get revenge for her. And that's what I plan to do!" Marie raised the knife and lunged forward toward Tony. Instinctively, he pulled the trigger on his gun, and Marie dropped to the floor, dead. From down the hallway, Tony heard Aiden and Aaliyah's screams of fear before they started crying.

"What's going o-" Janice, who had heard the gunshot and ran over from next door began. She stopped when she saw Marie lying on the floor, blood flowing from the bullet wound Tony had put in her head. "Oh my God!"

"Janice, can you take Aiden and Aaliyah for the night?" Tony asked as he walked toward the hall closet to pull out a sheet that he could use to cover Marie's body so his children wouldn't see it.

"Of course," Janice replied. Tony covered Marie's body and walked down the hallway to Aiden and Aaliyah's room, leaving Janice standing in the living room in shock as to what was laying in front of her. He walked inside to see Ziva sitting on Aiden's bed, her arm around a scared-looking Aiden, and a frightened Aaliyah on her lap. Tears were obvious on both children's faces.

"Are you guys okay?" Tony asked, joining Ziva on Aiden's bed and letting Aaliyah crawl onto his lap.

"What was that noise?" Aiden asked, taking his sister's place on Ziva's lap.

"Someone bad was inside, but it is okay now. Daddy took care of it," Ziva said, running her fingers through her son's hair. Ziva had heard everything that took place, so she knew it had been Marie.

"Janice is here, so you guys are going to go to her place for the rest of the night, okay?" Tony asked the kids. Aaliyah and Aiden both nodded their approval. Tony and Ziva stood from the bed, each still holding a child, and walked down the hallway and through the living room, trying to shield the twins' eyes from the scene as much as possible. Tony and Ziva set Aiden and Aaliyah down in Janice's living room, gave them a kiss, and told them goodbye before returning to their own apartment. Janice had previously called the police, so Tony pulled out his phone to call Gibbs.

"Yeah," Gibbs answered on the other line, just coming out of his sleep. Tony looked around at the living room and the events of the past few minutes raced through his mind as he tried to picture what his boss's reaction would be.

"Hey boss," he started. "You're not going to believe this."

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A/N: So there's chapter 13 :) I hope you liked it and that your questions regarding the case are now answered. I have two more chapters of this story for you though! Please remember to review and let me know what you think!