The Missing Piece of Evidence

I was hiding in a closet. A man in a police uniform was slowly entering the room. Then a pair of hands in white gloves appeared from behind him, holding a sharp knife. Blood stained the white walls. I never saw the man's face, but I did see that, beyond the white gloves, he wore a ring covered in petals...

That is my memory from childhood. As captain of the Jiashi Criminal Investigation Brigade, I've been searching ever since the day I became a police officer for the person who stole my childhood...