Bought property at trustee sale which is in probate

Hi,
I bought a property at a trustee sale which I later found out is in probate. The owner was an unmarried man and the PR for his estate is his brother. The brother and wife are currently living in the house. They have not paid the property taxes or HOA dues for the past 6 months. What is the procedure for getting the property vacated? Can I just send a 10 day notice (per MO law) or do I need to do something different due to proabte. Please advise. Thanks