When the old criminal police heard Lin Chen's question, he spat twice and said,"The water mixed with sand is a little salty…"
"That's right, it's salty and astringent."
Lin Chen snapped his fingers and smiled. He pointed at a pile of sand in the distance and said,"Sand might seem ordinary, but there are also differences in types.”
"There are mountain sand, river sand, and sea sand. They are all sand, but sea sand cannot be used as construction materials.”
"The salt content of sea sand is relatively high, and the amount of chloride-ions exceeds the standard, so sea sand is highly corrosive. Not only does it damage the concrete itself, but it can also destroy the passive film of the steel bars and corrode the steel bars. The lifespan of buildings that use sea sand is half that of normal buildings. Many buildings have mottled steel bars exposed because of the use of sea sand.”
"Sea sand can't be used to build houses, but black-hearted merchants and developers will still use sea sand as a building material because the price of sea sand is low, allowing them to obtain more profits.”
Lin Chen looked at the landlord and said,""The sand that you transported from the Gaiga layer is sea sand.”
Without waiting for the landlord to say anything, Lin Chen looked at Bao Qingshan and said,""The sand embedded in the anti-slip pattern of your shoes is sea sand. Although our Tian Hai City has the word 'sea', we are not a coastal city.”
"Qingshan Bao, tell me, why is there sand on the rooftop and under your shoes?”
Bao Qingshan stared at the photo of the sole on Lin Chen's phone screen and said in a panic,"Officer, the sand on my shoes is ordinary sand. Why do you say it's sea sand?”
"This is simple." "We just need to take out the sand from the soles of your shoes and compare it with the sand on the rooftop. Then, we'll know."”
"Damn it, he actually sold me some sea sand.”At this moment, the landlord cursed.
No one cared about the landlord's scolding. Bao Qingshan gritted his teeth and said to Lin Chen,"I haven't worn that pair of shoes for a long time. Even if there's sea sand in the soles, it might be something I put in before. You can't say that I must have been here just because of this.”
"That's right." Bao Qingshan's wife also chimed in." The place we used to live in was built by people. We had to walk past that place every day. Perhaps those people used sea sand to build the houses.”
Facing the couple's rebuttal, Lin Chen smiled and calmly asked Bao Qingshan,"Do you smoke?"
"I used to, but I quit.”Bao Qingshan replied.
"Have you been using drugs recently?" Lin Chen asked again.
Bao Qingshan shook his head." No, I haven't smoked recently. I've decided to quit smoking."”
"This guy, one moment he's on the soles, the next he's on the sand, and now he's smoking.”Miao Yunfei looked at Lin Chen's calm face and thought to herself.
Lin Chen looked at everyone and said,"Come with me."”
Everyone followed Lin Chen to the other side of the rooftop. Lin Chen pointed at a slightly grayish-black spot on the rooftop fence and said,"This is the mark left by a cigarette butt. This mark is very fresh. It's obviously left in the past few days.”
Lin Chen looked at the construction workers in charge of adding floors and asked them,"Do you guys smoke?"
A few construction workers waved their hands, indicating that they did not smoke. The landlord said on their behalf,""Officer, they don't know how to smoke. I can prove it to them.”
"Alright." Lin Chen looked at Bao Qingshan." The deceased didn't smoke. These construction workers didn't smoke. The landlord didn't smoke either…"
Bao Qingshan did not wait for Lin Chen to finish and said,""Are you trying to say that this cigarette stun mark was left by me smoking? There are so many residents in this building. Why are you blaming me instead of them?”
"First, the roof has been adding floors recently. The roof is a little messy, and ordinary residents won't come up to the roof to smoke.”
"Secondly, and most importantly, I found this on the ground below where the cigarette butt was extinguished.”
As Lin Chen spoke, he reached into his pocket and took out a sealed bag. In the sealed bag, there was a deformed cigarette butt.
"When I came to this rooftop yesterday, I found traces of cigarette butts on the fence. Someone smoked here, but I didn't see any cigarette butts upstairs. I think they were thrown downstairs.”
"So when I went downstairs, I went around to this side. Because this side is closer to the house next door, the alley is narrower, and very few people use this side of the alley. I found this cigarette butt in the alley. Then you can take this cigarette butt for a DNA test and compare it with your DNA.”
Bao Qingshan's expression froze, and his eyes became absent-minded.
Zhang Tianai looked at the cigarette butt in the sealed bag and suddenly remembered. She said,"I remember now. After we went downstairs yesterday, you made me and Xia Miaoyan wait at the door for a while before leaving.”
"Yes." Lin Chen said," You told me before that you interrogated these construction workers. They said that when they started work during the day, no one came up. In other words, someone left the cigarette butts on the roof at night. The roof is so messy. Who would come up to smoke at night?”
Lin Chen looked at Bao Qingshan and said," I don't need you to say anything now. I'll deduce the process of your crime and how you could kill the victim while having an alibi."”
……
This book comes from：m.funovel.com。