You can search for a case in Washington on the Washington Courts website http://dw.courts.wa.gov/
Click search by name. Then there will be drop-down boxes for the county in which she lived, the year, the court (you should select "Probate/Guardianship") and her first and last names. This should allow you to do exactly what you are looking for.
Hope that helps.
This posting is for informational purposes only. It is not legal advice, nor does it establish an attorney-client relationship. For more information, please visit www.justinelderlaw.com.
The probate would be a public record and you can check the county records as indicated.
The answer given does not imply that an attorney-client relationship has been established and your best course of action is to have legal representation in this matter.
Note that if she was a resident of Arizona at the time she passed, the probate would most likely have been done in Arizona. You would also want to check the appropriate court records in Arizona.
I am not your attorney. My response is provided for informational purposes only and does not constitute legal advice.