Since everyone didn’t have much to do, they all went to Peng Sijue’s office. There was a glass bottle placed on the table. Xu Xiaodong looked at the contents and was surprised, “It looks like Dirty Bread[1]!”

“That's liver that’s been soaked in formalin for three years,” Peng Sijue corrected.

“I know, it just makes me think of Dirty Bread... I’ll grab one to eat after work.” Lin Dongxue rolled her eyes at him.

Chen Shi said, “Why would they insist on using this harmful formula even though they have to pay out compensation every year? The answer is that it must be profitable.”

“It shouldn’t take long to figure this out since we know the result.” Peng Sijue picked up a pen and piece of paper. “I'll do the calculations now.”

It didn’t take long for Peng Sijue to fill the paper with lots of symbols and numbers. Everyone was dazzled as he nodded and mumbled, “Oh, so it was like that… That’s it…”

Xu Xiaodong said, “Captain Peng, can you explain it to us?”

“Don't interrupt him!” Lin Dongxue said.

After spending half an hour, Peng Sijue told them the results, “The online data shows that there are 2 million patients using this drug in the country each year and annual sales have reached 10 million boxes. I used this as a base to calculate. If they used the toxic but cheap ingredient, let’s call this ingredient B, they would earn about 60 million more than with the non-toxic but expensive ingredient A. If you deduct their compensation to families of victims, there is still profit. In other words, even if they have to deal with lawsuits and lose money every year, it’s still two percentage points more profitable to use the toxic formula compared to the non-toxic formula.”

Chen Shi became excited. “So, it’s as I’ve guessed. They have a set of annual profit calculations, and the lawsuit compensations are also considered as a variable. The deaths five years ago weren't accidents. They were part of the margin of error for this controlled variable.”

“It's terrifying!” Lin Dongxue frowned. “For the profit of two percentage points, they actually treat human lives as a joke?”

Old Zhang said, “For a large company, profit of two percentage points is astronomical.”

“I just made a rough calculation.” Peng Sijue said. “The real numbers shouldn’t be too different though.”

Chen Shi said, “This is a Pandora's box. Once this is made public, it won’t be as simple as dealing with a lawsuit. They would have to compensate everyone who has ever used this medication until they go bankrupt. That’s why they’d rather kill people to keep the secret from getting out.”

Xu Xiaodong asked, “The motivation is there, but how did they kill those people? Weren’t they “locked room cases”?”

“Let’s check the location out again!”

Chen Shi, Lin Dongxue, and Peng Sijue went to the place where the production manager Zhu Yan had died. This time, instead of prying the locks open, they got the keys from the real estate agent.

Standing in the empty room, Chen Shi said, “The door was locked, and the only key was on the victim. How did the murderer leave after he pushed him down?”

Lin Dongxue went over to look at the windowsill and said, “The windowsill is very narrow and there is a sewage pipe next to it.”

“Impossible!” Peng Sijue asserted. “The sewer pipe can't withstand someone's weight, and if there were footprints on the windowsill, the police would notice.”

Lin Dongxue suddenly figured it out, “It's actually very simple! After pushing him down, they can hold onto the key to lock the door, and then put the key back on the victim’s body afterwards.”

“That’s one solution.” Chen Shi said.

“After the person falls down, bystanders would come over. Can the murderer really manipulate the body like that?” Peng Sijue expressed doubt.

“There should be no one in the neighborhood around eight or nine.”

“If you are a murderer and you’re planning a fake suicide, a little uncertainty could ruin you.”

Chen Shi interrupted them, “Dongxue's divergent thinking is very good. Let's think further. The key might have actually been on the body. Why must the deceased be in the room? The deceased was anesthetized at the time and the murderer could have dragged him outside and pushed him downstairs at another location that would be in line with their window. That way, the key would be on his body.”

“The rooftop!” Lin Dongxue suddenly realized.

The three got to the rooftop and looked down. It was really high. They would definitely fall to their deaths if they fell from this height.

Chen Shi noticed that the edge of the rooftop had no railing on it. They had only painted a layer of red paint on the ground to indicate danger. Lin Dongxue said, “It’s scary to look down!”

“It wouldn’t be too painful to fall down,” Peng Sijue said.

“The few seconds in the air are scary enough.”

“During the rapid fall, some people faint, so they basically don't feel anything.”

Lin Dongxue grimaced, “I wouldn’t like that!” She stepped back and grabbed Chen Shi's clothes.

Chen Shi said, “If you fell from here, would you land on your front or back?”

Peng Sijue said, “It depends on the position.”

Peng Sijue's cell phone rang. After answering, he said to Chen Shi and Lin Dongxue, “They found a slight trace of sodium thiopental in the liver. It’s a vein anesthetic. It also has a certain effect when taken orally, and it’s not easy to detect... I’m glad we have enough samples.”

“You’re really efficient!” Lin Dongxue praised.

“It was undoubtedly a murder!” Chen Shi said, “In the photo, there was a large amount of dust on the victim’s back, indicating that he had been lying on the ground. He should have been lying down and fell down when he turned over. That’s why he fell face-down on the ground… Haha I understand now. The murderer placed the anesthetized victim on the edge of the rooftop, and then left him there. As the effectiveness of the anaesthetic gradually wore off, the victim turned his body in his sleep and fell off!”

“What if the deceased turned in the opposite direction?” Lin Dongxue asked.

“Most people have a fixed position when they sleep. For example, you like to sleep on the right side. You can make a guess by looking at the indentation on the victim's bed or pillow.” Chen Shi said, “This trick seems simple, but the actual effect may have been better than expected.”

Peng Sijue looked suspiciously at Chen Shi and then at Lin Dongxue. Then his thoughts returned to the case. “Delayed killings could make the deaths appear to be accidents as well as provide alibis for the murderer.”

“He used this trick three times in a row, and the police saw through none of the murders. The motive and the killing method are already clear. Let’s go and pay a trip to the suspect!”

“But we have no evidence!” Lin Dongxue said.

“Do you know any hackers?”

Peng Sijue said, “Do you want to use illegal means again?”

Chen Shi ignored him. “The president's computer may have documents about the algorithm. If you can get it, then we’ll have the evidence required.”

Lin Dongxue said, “I do know one. I'll go and look for him then.”

Chen Shi instructed, “By the way, get Xiaodong to check whether Hou Yue bought sodium thiopental three years ago. It’s okay even if he can’t dig up anything.”

Lin Dongxue went downstairs first, and Peng Sijue walked behind Chen Shi, saying, “You’ve influenced Dongxue negatively.”

“She’s clearly just levelling-up, okay?” Chen Shi laughed in response.

Chen Shi asked Xu Xiaodong in the bureau to check Hou Yue's current address. He went to his house alone, knocked on the door, and a thin man with glasses answered, “Who are you looking for?”

“Are you Hou Yue?”

“Yeah, who are you?”

Chen Shi showed his ID, and Hou Yue’s expression changed immediately. He grabbed the ID and opened it for a look. “You’re not a policeman?”

“I’m equivalent to the police. We have already opened a case to investigate your company.”

“Are you talking about the health club that was ordered to be closed last week for rectification?”

“Are you still playing dumb? I'm talking about Yuhua Company.”

“Yuhua Company?” Hou Yue adjusted his glasses. “I left that job three years ago.”

1. This is actually a mainland pastry fad.https://www.whatsonweibo.com/zang-zang-bao-hype-surrounding-beijings-dirty-dirty-chocolate-bread/