Because according to the evidence from the Crime Scene Investigation, it shows that the killer had been to the scene.
After the victim Zhang Cuilian entered the car and died, the killer opened the passenger side door, took something from the glove compartment, most likely the cash Wang Chuanzhi had put there, and wiped off the fingerprints on the passenger door handle.
In addition, the killer opened the trunk and took out a carbon monoxide generator that might have been prepared in advance.
"Where is Chen Gang?"
Someone asked, "Where is the victim's husband?"
Zhang Hui shook his head, "Even if Chen Gang could somehow get Wang Chuanzhi's car keys, he was on a business trip to Tianzhou City the whole time and only returned this afternoon, so he had no time to commit the crime."
Chen Gang only returned to Haizhou City this afternoon.
