Meitantei Conan S13E33 - ストラディバリウスの不協和音（間奏曲）

It is revealed that the house hold are killed off one by one in the order of the C Concert scale. The grandmother of the house was revealed to be emotionally shocked after the death of her son; Every midnight, she would leave her room carrying the Stradivarius like a child. That night, she breaks the violin, and falls out of the window. It was revealed the culprit taped up an object to lure her to the window where she would fall to her doom.