How come NPCs can Own property in this game, but the Dovakin cannot?

Seriously. So I'm at that point of killing Gerald the Kind. The dagger is my enchantment, I named it. I pick pocketed it into her assistances pocket. Fury spelled the assistance, she killed Gerold the kind, time to get MY dagger back.

Apparently it's considered stealing just to get MY dagger back.

WTF. I should be able to own my property. She was just borrowing. And considering that I furied spell her and made her kill Gerald the Kind. Shouldn't the DB be contacting her not me?

My hands are completely clean.

Well, technically you did give it to her...

I let her borrow it for a certain amount of time.

There should be an option that goes

You're pick pocketing a person would you like to for ownership

-Relenquish item into [insert name here]

-Item Belongs to Me, allows in pocket for [insert game amount of time]

IDK, I don't what. But it's still my dagger. I didn't give it to her. She was to borrow it and I take it back

1. The way I look at it, it's irrelevant whether it's your dagger---the act of dipping around in a person's pockets/clothes without their consent is criminal by itself. Here's another way of looking at it: I leave something in your house, without telling you, and without you knowing I've been there. Then I come back another time, without you knowing, and take it. Have a committed a crime? Well, yes, I've trespassed, even though I may not have stolen anything.

2. You definitely killed Grelod. If you do something that predictably and reliably causes death (in this case, giving someone an enchanted dagger that will make them attempt to kill nearby people), that's killing. The assistant also killed Grelod, but didn't murder her, since she wasn't in the appropriate state of mind, so that's why the DB don't contact her.

It was pretty funny to watch none the less.

He just fireballed her in the face for having his dagger and not giving it back. Now those orphans are really orphaned in Whiterun. Who takes over now?