回複：回複：不是說話的聲音，而是莫名其妙，肆無忌憚的撞擊碰撞聲，非常響，當是由於那個人的習性所致。

Thank you for providing the necessary informations and helping to envision the possible scenarios. Especially with B), I shall need to think of how to present the situation to the police officer when he arrives.

Thanks again.