My Grandpa's Brother Took All His Stuff, Is There Any Legal Action We Can Take To Get Some Back?

Recently my Grandpa who lives in Arizona passed away. His brother was with him at the time and we all live in different states, so we let his brother handle things while we got ready to go to see him. Well, my Aunt and Uncle got there today and it turns out that my Grandpa's brother cleaned out his house. He took everything including my Grandpa's clothes. The only things he left were the keys to the house and the registration for a really broken down car on the property. As far as I know, my Grandpa didn't have a will. He's not very wealthy or anything, and we thought that almost everything was going to go to my Uncle since he was the closest to my Grandpa. The only thing my mom wanted was my Grandpa's motorcycle. Is this not technically against the law since my Grandpa didn't have a will? Is there anything we can do to get some of his stuff back?