Believe my brother misrepresentated his POA intentions

My aunt originally appoined me as her exceutor.During her hospitalization I requested she change it to my brother who lived closer and would be more readily available to assist her and any problems she had. My sister in law(works for an attorney) also insisted he be made POA. My aunt agreed. My aunt is still alive and my brother and sisiter in law go to her home and begin packing everything up, selling items etc. My aunt was devastated. She passed last July. I am the sole beneficiary of her will with an neighbor getting $1000.00. Thus far I have seen not one dime - NOTHING. They cleaned out her home, everything is gone and when I asked about her jewlery - I was told it was at their home and they would get it for me to see. Most was clearly not my aunt's jewlery. I asked about the glass rooster with her sapphire and diamond ring and they told me there was no rooster and ring. The neighbor said it had been there, also bags of "trash" at the curb contained family Bibles etc. What can I do