“Flat awl?” Chen Shi rubbed his chin. “Are there other findings?”

“The victim's teeth were loose and there were several bleeding points on the gums and inside the lips. We found a bottle of medicine on him,” Peng Sijue said as he held up a plastic bottle with a label that was fully-written in English. “It’s labelled as a sleeping pill. The ingredients have to be tested, but in addition to this, there’s an even more critical clue. There seems to be dandruff under the nails of the deceased.”

“That's great. Just check the DNA of all the passengers and we can lock onto the killer,” Lin Dongxue said.

“Let me see!” Chen Shi said.

Peng Sijue took the hand of the corpse and put a magnifying glass in front of it. Chen Shi looked into the gap between the nails for a while and questioned,...