Accepting a gift from the father of a thief

An antique was gifted to us by the father of a friend who later was revealed to be a crook. He cheated us out of business and various mechanisms. We were unaware at the time he was an employee. This antique was gifted to us by the father of the crook who does not have good relations with his son who has gone astray. It is fully certified and carries the paperwork of authentication at Ministry of Tourism level. Hence our confusion and 2 scenarios:

1. Is it permissible to sell this antique and use the money for ourselves, since it was from the father and not from the son? Is it jaiz to assume a father might be like his son, the warning of making lawful things prohibited as in Surah Tahrim comes to mind. As well as the warning of acting on unfound suspicion as in Surah Hujarat. The father could be completely innocent.

2. If it is not permissible to use the money from the sale of the antique out of suspicion and caution, its not pure enough for sadqah either. Can it be used to pay off debts incurred by the scheming of this ex-employee? Kindly advise what to do with the money once the antique is sold. How may it be spent?