أَأَضَاعَ الْأَمِينُ الْمَخْطُوطَاتِ؟
Did the custodian lose the manuscripts?
If the speaker seeks information, this is a genuine question, even if the question carries suspicion. If the speaker already knows the manuscripts were not lost and uses the same wording to reject an allegation, a negative rhetorical reading may arise.
An interrogative hamzah alone cannot determine the rhetorical function. The questioner's knowledge, purpose, delivery and context are all relevant. The present dialogue supplies a genuine inquiry followed by a corrective denial.