All monies used by law enforcement officers or agents, in the line of duty, to purchase controlled substances during a criminal investigation must be returned to the state or local agency or unit of government furnishing the monies upon a determination by the court that the monies were used by law enforcement officers or agents, in the line of duty, to purchase controlled substances during a criminal investigation. The court may order a defendant to return the monies to the state or local agency or unit of government at the time of sentencing.