C699 Ask and Kill Again

"This is very strange?"

"The killer must be hiding on this train."

"But as long as it's a human, no matter where he goes, he will leave his aura behind."

"Only a person or a monster that has mastered the mysterious power can leave no traces of his aura."

"There were no traces of humans at the scene, but the deceased died from a gunshot wound. The problem is very strange