There was a killer who would light a candle next to the deceased after killing him.
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When Jiang Jing went to the police for the first time, he found a burned out candle next to the body of the deceased at the crime scene.
After that, at every crime scene, a candle would be found next to the deceased.
But every time, the investigation of the previous case is not completed, and the next case comes.
Until the case happened in a university
A student took the initiative to cooperate with the investigation and later became a good helper for Jiang Jing.
Intention: What made him have no choice but to kill someone?