Sister In Law used deceased mother's credit card after her death Fraud, Embezzlement, Bad Checks

My sister-in-law was the POA for my mother-in-law and spent a huge amount of her money before the woman died. AFTER she died she continued for over 2 months to use the credit card to buy inventory for a business she owns as well as plane tickets!! American Express settled the account with the estate for 50% of what was owed, but i am wondering if we have legal recourse with her spending the money on a credit card after my mother in law was dead.