From the direction of the bloodstains, it's clear that someone took the ax from the courtyard, went into Lizheng's bedroom, killed Lizheng in his sleep, returned to the courtyard, and put the ax back.
The ax handle was engraved with a "Ma" character, which indicates that this ax was indeed the murder weapon.
The disappearance of the blood traces by the stump also suggests that the murderer did not leave the yard.
Of course, one could also assume that a murderer, who could nimbly traverse roofs and walls, left the crime scene without leaving any traces.
But this game isn't set in a wuxia novel; instead, it's in a poor, remote little mountain village. Bai Youwei doesn't believe that the game would create characters incompatible with its context.
She thought, just like Shen Mo said, the murderer could either be the corpse carrier woman or one of the villagers here, with no third possibility.
