Help Detective Barnaby complete his official suspect report by choosing the grammatically correct word.

The mysterious man in the trench coat, to _____ the stolen diamond was allegedly given, has vanished without a trace.

The correct answer is whom.

In formal English, we use the object relative pronoun whom immediately after a preposition (like to, for, with, or about). Since the diamond was given to him, he is the object of the preposition, making "whom" the perfect choice for a professional police report!