Summary: Casey confronts a family problem. No ships. Histories not necessarily the same as in my fanfic "Ridiculous." Spoilers for episode 3.11 "Ridicule."

Chapter 1

Disclaimer: All characters owned by Dick Wolf and NBC. No money was made by me on this work.

Olivia had just explained the basics of the case to Casey. The latter was feeling the bridge of her nose and nodding slowly.

"Okay, I got it. I'll make the motion, and then I'm off for the day."

She paused a second. "Olivia, can I talk to you for a few minutes after work? At the bar where we all hang out. I need your perspective on something."

"Sure."

As Olivia walked out of the office, she noticed two cops quickly shutting up and one of them putting a piece of paper in his pocket. Oh, good. It was the Elliot/Olivia pool. Some idiots had got it in their heads that because she and Stabler worked together, they must have the hots for each other. Since she saw Elliot almost as a brother, this was really creepy. She would have said something about it, and complained about the sexism, but then she heard about the Fin/Munch betting pool, and the now discontinued Alex/Olivia betting pool, and decided that talking about such pools would probably lead to learning something about such pools, a thought which filled her with much dread.

Soon afterwards, she met Casey at the bar.

"So, what is it you wanted to talk to me about, Case?"

"Olivia. Your mother was raped, wasn't she? That's where you came from?"

"Thank you for being so subtle and diplomatic. That's what I love about you."

"Okay," said Casey, putting her hands up in surrender. "That was a little abrupt, I know. But I wanted to ask you how you live with it."

"With what? With being a child of rape? With feeling that I owe my existence to something that I am fighting to prevent?"

"No, with the fact that he is part of you."

Olivia started. "What… what do you mean?"

"I checked around. There was a case a few years back with a rapist whose father was a rapist. You were somewhat worried, according to your friends. Apparently, the boy used a genetic defense, and you wondered if you had a genetic predisposition to violence as well?"

"Yes. So?"

"Do you ever worry. Do you ever wonder if you have it in you to… to rape someone?"

"Yes, I suppose. Although I am usually more worried that I would hurt someone in… well, through more non-sexual violence. You know, beat them up."

"Being female must be a bit of a relief for you. Given the stats, it's likely that even if you had inherited some 'rapist' gene, it would be, well, dormant in you, because, you know, you're a girl."

"Well, perhaps."

"Well, let's just say that if your mother had been the one to attack your father, you'd have a lot more to worry about, in terms of your own predispositions."

"Listen, Casey, that's not funny. What the hell is this about?"

"Olivia, I was adopted. I didn't know my birth parents. But I recently found out that I have a sister."

"How?"

"Well, my sister and I were put up for adoption at the same time. We were mistakenly separated and the paperwork indicating our relationship was lost. It was found again recently, and after checking both of us for consent, it was released to each other."

"So?"

"My sister is a rapist. And, a murderer."

"Oh."

"It gets worse. Most sisters share 50 of their DNA, 25 for half-sisters. We shared more than that."

"I don't understand."

"We're identical twins."

"Who's your sister, if I don't mind you asking?"

"Hell, your squad arrested her, you should know. Don't I remind you of anybody?"

"Oh, Hell, no…"

It was back in 2001. A woman had been found hanging from a ceiling fan in her apartment. At first it was ruled death by autoerotic asphyxiation. She was being kinky and had an accident. Turned out she was a pain-killer addict who had wound up raping a male striped with two of her friends. The case had helped to propel Alexandra Cabot to fame, and had set precedents. It also turned out that she had actually been killed by her two so-called friends when it seemed that she might rat them out.

The two friends were real pieces of work. One of them was a misandrist day-trader who, the other was a cold, ruthless defense attorney who seemed to think that everyone else in the world existed for her benefit. The day-trader was into asphyxiation, and she was the one with the idea to hang her friend and make it look like an accident. She had pled guilty to rape and murder. The attorney had gotten of on the rape charge, but later pled to the murder charge and was serving a 25-year sentence.

The day-trader, now that Olivia thought about it, was the spitting image of Ms. Novak.

"Oh my God. You're Amelia Chase's sister!"

"Yup. You have half of the genes of a rapist, Olivia. I have all of them. And, her being female, I don't have the comfort of saying 'well, those genes only work on males,' now, do I?"

"Recently."

"What?" asked Casey.

"You said you learned recently that Amelia Chase was your sister. How recently?"

"This morning. The results were emailed to me."

"Oh, my."

"There's more."

"What?"

"I'm visiting her in prison tomorrow."

"Why?"

"To see how much we are alike. Am I just her in different circumstances? Why did she become what she is? Why didn't I?" Casey thought a moment. "May I ask you a question?"

"Sure."

"How did Ms. Chase strike you? I mean, you did meet her, didn't you?"

"Not really. Munch and Fin dealt with the investigation and arrest. Cabot did most of the talking. I only saw her once or twice. Didn't speak to her a great deal."

"Any thoughts from that?"

"Well, she definitely hates men. I got the impression that she enjoyed the idea of victimizing men. Ms. Adler, on the other hand, just seems arrogant. I think she just wanted sex, and decided that she could get away with forcing herself on the victim, so she went for it. Ms. Chase - she wanted to rape him."

"Oh, joy." Casey was beginning to wonder if this was a good idea.