I provided a link with further details in a post above. There are many others available with a simple google search. We will just wait and see how this case works itself out. In most states with Castle Laws if you are physically assaulted on your own property then you have the legal right to shoot the perp anywhere on your property.... especially if they were in the middle of stealing your stuff when they assaulted you
It's been a long while since I was versed in the various state laws as a firearms instructor, but Florida has (had) one of the most lenient slates of regulation on the whole "Castle Doctrine" bit. It was (is) called forcible felony prevention. In that you were allowed to use deadly force to prevent a forcible felony. If I recall, one of those was theft/vandalism of your personal property. Pretty darn extreme if I must say. Does Washington have that same level of standard?
My understanding is that Washington State does not have a Castle Doctrine law. There are some unclear laws around duty to retreat (or not) but no Castle Doctrine for the state of Washington. First google search result - https://lewiscountywa.gov/media/attachment/4500/BrochureUseofDeadlyForce052011.pdf