Scene:
You chose your victim, a random person. In the mountains you took them, but you decide that you're going to shoot them in the spine and leave the body in a ditch.
As a treat for yourself, you take something small. Insignificant, you tell yourself. Nobody's gonna miss the ring or necklace.

Scene!!

What can you tell me is wrong with that scenario?

First- if you got to the mountains in a vehicle, PRAY that no surveillance cameras captured the license plate number. If you OWN the car or know someone who does, that is a double whammy. Get your victim into your desired spot by foot or by biking. Don't threaten them, if you do bystanders can testify against you.

Act jovial. Be friendly.

Second, a GUN?! It's loud, even if you think you're alone don't bet on getting away without somebody hearing something. A mountain? Just push the victim off a cliff. Preferably after enough drinks to make them tipsy.

That also gives you a great cover story:
The victim got drunk and decided to walk this mountain trail. You went with them to make sure they were okay, but they slipped and fell off the mountain. Tears, tears.

Anyway, final thing-

DO NOT TAKE A STRAND OF HAIR FROM THE VICTIM UNLESS YOU WANT TO BE CAPTURED.

NO JEWELRY, NO BODY PARTS, NOTHING.

otherwise I'll fail you immediately from this course.