Richard Castle: Looks like she was stabbed with a knife.
Kate Beckett: Mmm.
M.E. Sidney Perlmutter: To the untrained eye, perhaps. But... what you don't know about postmortem analysis could fill a book, Mr. Castle. In fact, it has. Numerous times.
Richard Castle: Fine. So, it was not a knife.
M.E. Sidney Perlmutter: Ah, wrong again. It was a knife, but "stabbed" implies the blade was thrust into the victim, uh, whereas this wound was produced by it being hurled into her chest.
Kate Beckett: What is this, "Last of the Mohicans"? What kind of knife is it?
M.E. Sidney Perlmutter: Uh, one with a hilt that matches these small bruises on either side of the wound. It killed her instantly, severing the left anterior descending artery.
Kate Beckett: Okay, so either that's the luckiest knife toss in the world...
Richard Castle: Or, she was killed by a circus knife-thrower. Like the Great Throwdini.
Richard Castle: So you, being the expert veteran of dozens of crime scenes, decided to pick up the murder weapon, to what? Ensure that we had your prints?
Richard Castle: Maybe you missed the part where I said she was shot dead. When I heard the noises coming from the next room, I thought whoever killed her was coming back. So I picked up the gun to defend myself. It seemed like a very good idea at the time. That's when you, Esposito, and Annie Oakley come bursting through the door.
Captain Roy Montgomery: Annie Oakley?
Kevin Ryan: I kind of almost shot... Castle.
Kevin Ryan: What? He had a gun.