Chapter 122: The Killer Had Planned It All Along—A Prearranged Dinner Gathering!

Can a capsule-sized amount of potassium cyanide powder cause death in a short period?

Su Ming’s question immediately lit up the eyes of everyone present, as they all simultaneously thought of a particular possibility.

Shen Lin paused for a moment, then used her professional expertise to respond with certainty.

“Of course it can.”

“Take commonly used domestic medication as an example—the powder inside a capsule typically weighs between 0.5 to 1 gram.”

“Of course, this refers to the weight of the powder inside the capsule, not the capsule itself.”

“The lethal dose of potassium cyanide is around 0.1 to 0.2 grams, enough to cause death in an adult in a short time.”

“If the dose increases to 0.5 grams or even more than 1 gram, then once the capsule shell dissolves, it will certainly cause the person to lose consciousness, suffer muscle convulsions, and die from cardiac arrest within a very short period.”

“A large dose of potassium cyanide taken in a short time would cause sudden cardiac arrest and instant blackout, making it impossible for the victim to cry out for help.”

“Moreover—”

“If the capsule shell is made from different materials, the time it takes to dissolve in the stomach will also vary, which means the time of poisoning can be controlled to a certain extent.”

“And the most important point is…”

“Even though cyanide causes rapid death, gelatin-based capsule shells dissolve easily in warm water.”

“So even if the victim loses vital signs, the capsule shell will fully dissolve as the body temperature gradually drops, leaving no trace of the shell in the stomach contents during autopsy.”

“Cyanide is absorbed through the stomach lining and quickly enters the bloodstream.”

“As long as the victim’s body is discovered more than an hour after death, then judging by the symptoms alone, the cause of death from ingestion or injection would be virtually indistinguishable.”

After Shen Lin laid out these professional forensic facts, even Liu Yang—who had transitioned more into political work and was no longer focused on crime scene investigation—immediately understood the purpose behind Su Ming’s earlier question about capsules.

Bai Yu, dressed in a suit and fiddling with a pipe, pondered as he analyzed:

“Going by what Brother Ming is suggesting…”

“Then the method used in the theater poisoning case should be—”

“The killer didn’t inject the poison into the victim using a syringe. Instead, they concealed it inside a capsule.”

“By manipulating the gelatin shell, they could roughly control the timing of the victim’s poisoning.”

“And then—”

“The needle puncture on the victim’s buttocks might’ve just been a red herring, a distraction… but it seems we’re getting close to narrowing down the suspect.”

“First, a normal person wouldn’t just accept and take medication from a stranger. If the victim took a capsule that led to their death, that implies…”

“The killer likely knew the victim—and their relationship was close enough to allow them to swap the medication.”

“Second, creating a needle mark on the buttocks wouldn’t be difficult if the two were close—maybe during horseplay or by hiding a needle in the bed.”

“With that line of reasoning—”

“The killer is likely someone close to the victim, someone familiar.”

“Logically, when a case occurs, the people closest to the victim are the first to be ruled out. But the unique nature of potassium cyanide may have caused the crime unit in Xiangcheng to overlook this.”

“Because—”

“Cyanide kills extremely fast. Within minutes—or even seconds—it can cause death through cardiac ischemia.”

“Add to that the needle wound on the victim’s buttocks found during the autopsy—it naturally drew police attention to the theater seats or people present at the scene.”

“The real killer, however, only needed to ensure they had an airtight alibi for the time the capsule dissolved and the victim died. From the police’s perspective, that would’ve cleared them of suspicion entirely.”

“This technique is quite common in Conan or other mystery cases.”

“But we have to admit—it’s quite effective in avoiding police scrutiny, especially when paired with cyanide’s lethality.”

“It’s easy to miss…”

At this point, Liu Yang seriously tried to recall something for several seconds, then frowned and shook his head.

“No, something’s off.”

“I just remembered—back then, even though the Xiangcheng crime unit focused on people around the theater and anyone with motive…”

“We were also thorough and investigated whether the victim had been taking any medication or had sought medical attention.”

“But there were no results—at least in the weeks prior, the victim had no hospital visits or medication purchases on record.”

“There were also no traces of drug metabolism in the blood sample from the autopsy.”

In response to Liu Yang’s objection and confusion, Su Ming didn’t hesitate and promptly replied:

“Director Liu, you’re forgetting a detail.”

“I checked the case files yesterday. The victim was a software engineering graduate from a modest background, who had applied for financial aid.”

“He even took out a government student loan to cover tuition. He lived very frugally. It wasn’t until he started working as a programmer that his finances improved a little—enough to go to the movies and such.”

“But based on his frugal habits, is it possible…”

“That he kept unfinished medicine—like leftover cold medicine—to reuse the next time he got sick?”

“If his discomfort was due to the same recurring symptoms, then he wouldn’t have needed to buy new meds—just use what he had.”

At that moment, Liu Yang froze. The Xiangcheng team had completely overlooked that detail.

But Su Ming wasn’t finished. Narrowing his eyes, he continued analyzing.

“Compared to cold medicine…”

“I actually believe the killer might’ve disguised the potassium cyanide as stomach medication.”

“Because of the victim’s programming job, he likely worked overtime and had irregular meals. During college, he probably skipped breakfast to save money.”

“Surveys show that students from poorer backgrounds have a significantly higher rate of stomach issues compared to wealthier students.”

“Stomach pain usually occurs late at night after meals or in the morning without eating.”

“The victim was poisoned late at night—I suspect he took what he thought was an omeprazole-like capsule ahead of time to prevent stomach pain.”

“Most long-term stomach sufferers keep painkillers on hand. For someone as frugal as the victim, he definitely wouldn’t have gone to the hospital every time—keeping backup medicine is perfectly normal.”

“But here’s the real issue…”

Su Ming paused for two seconds, then lightly tapped the whiteboard, narrowing his eyes and speaking slowly.

“If the victim had chronic stomach problems, then he would’ve been cautious—not overeating, minimizing triggers.”

“Then why did he take the stomach medicine in advance on the night he was murdered?”

“Did he anticipate the pain that night?”

“Or…”

“Did he already feel unwell, but didn’t want to miss the movie he’d paid for—so he took the medicine to endure it?”

“So now, I strongly suspect that on the night of the murder, the victim had a special dinner or social gathering he couldn’t refuse.”

“And the killer planned this entire cyanide capsule murder around that prearranged dinner…”

“…in a private theater poisoning case!”