CSI: Crime Scene Investigation, Season 1

Alan Rich:
So you really pulled this out of a corpse?

Sara:
Yeah ... but I cleaned it for you.

Brass:
We need to know the make of that knife.

Alan Rich:
Well, it's not a knife. The tip's double-edged. Bevels on both sides, downward slope. This came from a dagger which means it's either carbon steel or stainless steel. I get asked this question more than you think. (He pulls out a lemon juice squirt container and puts a few drops on the tip of the knife.)

Sara:
(explains to a very confused Brass) Acid in the lemon juice should react to carbon steel, but not stainless steel.

Alan Rich:
How's a cop know all this?

Sara:
(smiles) He's the cop. I'm the scientist.

Brass:
I got a cop question. What are we looking for here?

Alan Rich:
Dark spots. (The tip has dark spots on it.)

Sara:
Carbon steel. What's next?

Alan Rich:
Length. (Alan turns and looks for something behind the counter. He comes back with a piece of paper and a ruler.) Daggers are rarely more than an inch at the base. We got the tip. So, we can fill in the rest. It's basic geometry.(Placing the tip on the piece of paper, he extends the tip of the dagger to estimate how long the weapon used was. It's five inches. Top row, five-inch daggers, carbon steel.(He reaches into the display case and takes out a dagger to show them.) This is the one you want. $24.99. We don't take credit cards.

Brass:
Yeah.