Last Moment before the Crime

It was so strange!Usually amiable geography teacher Mr.Wang had a "e;too-late arrival"e; at this day class. He entered the class room without saying hello and smiling. He not only took wrong English textbook to attend class, but also answered a phone even during the class!Mr.Wang didn't say a few words to the phone, then he suddenly fainted.Xiaorou picked up Mr.Wang's phone and listened to it. She heard a cold and ruthless voice from the other end. Who was the other end of the phone?What on earth did the person say that made Mr.Wang faint with excitement?Zhang Xiaorou turned into a young detective!All the riddles would be solved one by one!