Chapter 173: Cause of Death

The cause of death is a profoundly serious matter for forensic pathologists.

Forensic pathology, the entire book, is about this very thing.

The court also places extreme importance on the cause of death.

Take today's case: if death resulted from arson—that is, the victim died due to arson—but the arson was not targeted at the victim, it could lead to a life sentence.

But if the killer set fire after murder, that constitutes an aggravating circumstance, and it's almost certainly a death sentence.

On the other hand, if the victim was accidentally killed in the fire, or murdered first and then the body was burned by someone else, it might revert to a life sentence.

Niu Dong's expression grew grave as he took the lead in the autopsy.

Burning a body after murder is relatively common.

Killers often employ various methods to destroy evidence and conceal the crime.

But the abdomen was stabbed so many times, yet the lungs showed crepitus…

These are two entirely different causes of death.

Crepitus in the lungs—or a snow-grip sensation—typically indicates asphyxia.

Niu Dong decisively cut a piece of lung tissue; pink, frothy fluid oozed out.

This further confirmed that death was very likely related to asphyxia.

So, did the victim suffer abdominal stab wounds, lose consciousness, then die from smoke inhalation?

Niu Dong's gaze instinctively turned to the victim's throat.

It is well known that bodies killed by smoke inhalation have three characteristics.

First, the airway and mouth may be burned by high-temperature smoke. Second, the eyes are usually closed. Third, carboxyhemoglobin saturation is elevated.

The first point is easy to understand.

The second is also straightforward: smoke is highly irritating; at lethal levels, one would inevitably close their eyes while exposed to it.

The third point—elevated carboxyhemoglobin saturation—is an indicator of carbon monoxide poisoning.

In healthy individuals, this marker is typically negative; in smokers, it may range from 0. 2 to 0. 4.

But if someone suffers carbon monoxide poisoning in smoke, carboxyhemoglobin saturation spikes above 20%.

However, whether the eyes were open or closed is hard to verify.

After death, eyelids can be closed manually—for instance, some men, weeping in the fire, cover their brother's eyelids, raising suspicion they strangled him and concealed the cause.

Carboxyhemoglobin saturation requires toxicology testing to confirm.

Originally, for forensic pathologists, the most direct method was to cut open the airway and take a look.

But the victim's anterior chest tissue, including the throat, had already carbonized; Niu Dong made a cut and saw nothing, so he stopped.

"Should we take blood for testing?" Jiang Yuan asked politely.

"Hmm… yes."

Niu Dong's response lagged slightly behind Jiang Yuan's.

Taking blood is for toxicology testing.

Jiang Yuan volunteered again: "I'll do it?"

He was here for training; he couldn't just linger on the sidelines.

Niu Dong paused, then stepped aside to let Jiang Yuan take his place.

Jiang Yuan collected blood and gastric contents.

Toxicology testing primarily focuses on these two samples.

One reveals what's in the blood; the other, what's in the stomach.

After collecting the samples, Jiang Yuan lightly tapped the abdominal cavity with his scalpel and asked: "Check inside?"

Wang Lan and Niu Dong blinked, then murmured: "Go ahead."

They didn't need him to specify what to look for; all three forensic pathologists leaned in together.

"No clots."

"The stomach was punctured, but no clots, no carbonization."

"The lower abdomen too—no carbonization."

They silently voiced the key points in unison.

If a vessel was ruptured before death, it bleeds—because the heart is still pumping.

If ruptured after death, it doesn't bleed—the heart has stopped.

The reason you can't get blood-drained pork in Europe and America, beyond economic and cultural factors, is that draining blood requires the pig to be alive—something considered uncivilized.

The absence of clots in the abdomen suggests the vessels were punctured after death—or…

Theoretically, clots could have been burned away by the flames.

Mentioning no carbonization in the stomach or lower abdomen eliminates possible alternative explanations.

"So, toxic or mechanical asphyxia seems most likely—and after death, the body was stabbed so many times…" Niu Dong shook his head.

Jiang Yuan gestured to the stab locations: "Possibly someone familiar—feared recognition, so added more stabs."

"Very likely," Niu Dong said, excited. "I'll call right away."

The cause of death was essentially determined.

Specifics still depend on toxicology reports, but the fact that the abdominal wounds were postmortem significantly impacts the investigation—must notify frontline officers first.

After Niu Dong washed his hands, made the call, and re-gloved, he saw Jiang Yuan and Wang Lan had extracted the heart and were examining it closely.

"Any findings?" Niu Dong hurried onto his stool.

"Petechial hemorrhages," Jiang Yuan said.

"Asphyxia corroborating evidence," Niu Dong nodded.

Asphyxia causes hypoxia, producing such petechial hemorrhages on multiple organ surfaces.

The victim's heart showed exactly this.

Yet, given today's body condition, noticing petechial hemorrhages was difficult.

The thoracic cavity was nearly burned through.

If the fire had burned slower and consumed the entire house, the heart would likely have been fully incinerated.

"Jiang Yuan has sharp eyes," Niu Dong remarked approvingly.

Wang Lan lifted his head, rubbing his neck, and added: "Jiang Yuan isn't just sharp-eyed—he specifically looked for hemorrhages on organ surfaces. He checked the liver and kidneys too. The heart's hemorrhages were already dried, but he still found them."

"Jiang the forensic pathologist is capable," Niu Dong nodded.

Knowledge is in books—but applying it at the right moment, appropriately? That's not simple. Niu Dong's assessment of Jiang Yuan had shifted from "young newcomer" to "slightly higher regard."

"Let's finish the rest—the team leader Lei Xin is coming to check soon," Niu Dong said, resuming his work with renewed vigor.

Cao Keyang, the trace evidence technician beside him, sighed, nearly nauseated: "Your team leader's coming now? At midnight?"

"He never sleeps at night. No problem," Niu Dong showed zero concern for his superior's well-being.

Jiang Yuan, Wang Lan, Cao Keyang, and the forensic assistant all nodded in agreement.

The atmosphere in the autopsy room grew unexpectedly warm.

An hour later, Lei Xin, captain of the criminal investigation unit in Qianjin District, Qinghe City, arrived.

"Forensic Jiang, thank you, thank you for your hard work."

Qinghe City has three districts; Qianjin District is an old urban area, and its criminal investigation unit ranks equally with Ningtai County's.

He was a thin man with yellow hands and yellow teeth—clearly suited for thinking, not physical work.

Upon entering, Lei Xin first politely greeted Jiang Yuan, then offered cigarettes to the others.

Jiang Yuan said, "No trouble," took a cigarette, and lit it.

Excessive flattery always has a motive.

Seizing the opportunity to build rapport, Lei Xin added: "Forensic Jiang, Forensic Wang, Niu Dong, let me brief you on the case?"

"Good."

Lei Xin chose his words carefully: "Briefly, today—yesterday afternoon—a residential house in Qianjin District, a self-built home, caught fire. After extinguishing it, we found this female body… DNA comparison results just came in."

"The victim is Zhang Ying, 22, unmarried. She rented here. The scene showed her lying naked on the bed—possible home invasion rape."

"Self-built homes in urban villages have complex foot traffic and few surveillance cameras."

"We're currently investigating Zhang Ying's social circle. She worked at a mall as a sales clerk for L'Oréal, but had no close colleagues. Her parents knew little about her social relationships…"

After outlining everything, Lei Xin asked: "Forensic Jiang, would you have time to inspect the scene?"

Jiang Yuan didn't object, but rubbed his head: "After arson, evidence is scarce."

He'd previously handled fingerprints in an arson case—his limit.

Lei Xin didn't hide it: "The scene yielded almost no evidence. If we find no semen or similar proof, even if we identify a suspect, we'll lack physical evidence."

"The weapon?"

"The weapon was found near the origin of the fire—a chef's knife, Western-style, part of a five-piece set in a wooden box. The exterior is completely charred."

Honestly, despite his flattery, Lei Xin's current problem was genuinely difficult.

Lei Xin complained half-seriously: "Our investigation hasn't yielded results yet. Even if it does, I still have to worry about physical evidence. Modern homicide cases demand more and more—without DNA or solid physical evidence, prosecutors complain."

Wang Lan nodded in deep agreement: "CSI effect."

The CSI effect refers to how excessive exposure to TV shows, movies, and variety programs about forensic science has subtly raised public expectations of forensic capabilities.

In Europe and America, the CSI effect manifests as jurors demanding more DNA testing and advanced technologies.

In China, the CSI effect is more evident among leaders—especially non-specialist or higher-ranking ones. When they ask about "physical evidence," investigators inevitably feel pressure.

To some extent, this is actually progress—leaders demanding "physical evidence" seem more scientific than those demanding "confessions."

For someone like Lei Xin, a grassroots supervisor, everything had to be taken into account.