By that token, there is no life and just a collection of specifically arranged atoms. There is no murder, just metabolism alterations by a third party.
You're certainly right about murder. You wouldn't say that a cat "murdered" a mouse, you would say a cat killed a mouse. Just as when a dog has a bone, you wouldn't say the dog "owned" the bone. There's a difference between material reality (such as life, killing, and physical possession) and the moral framework you attach to it (like murder and ownership.)
Ownership is something a government does for you, and encompasses whatever arbitrary rules that government imposes and is willing to enforce. That's why this is a discussion about what courts should do.
I would say a cat murdered a mouse, in particular because cats seem to kill a lot of small animals for no practical reason (as opposed to hunger, for example).
If you're suggesting there's a valid moral code where murder is ok (for humans), well, I guess that's a matter of opinion, but I expect many people will disagree with you.
