Murder

Qin Xuan really didn't see anything wrong. There was no fracture or bleeding. What did Mo Li mean?

Mo Li glanced at Qin Xuan. He is still inexperienced so he doesn't understand many things. She pointed at the base of the skull and said, "Do you see the protrusions on both sides of the base? They are called petrosal bone."

Mo Li used a clamp to point at the petrosal bone. Mo Li added, "This bone is connected to our inner ear. If one drowned or died from lung failure, the inner pressure will change and the petrosal bone will not bleed." 

Qin Xuan nodded. He was first in class and he did know the theory behind this petrosal bone. When he saw the victim's blackened petrosal bone, he came to the epiphany. "If the victim did die from natural death, then her petrosal bone wouldn't have turned black."

Mo Li nodded. "That's right, so the only explanation is that this is murder."