Diary of a Criminal Investigator

Chapter 113: DNA Information Comparison Results


Criminal Investigation Team Meeting Room No. 1.

Liu Guodong was reporting on the crime scene investigation findings.

"Firstly, regarding the identification of the first victim, we still have no results on fingerprint and DNA information matching."

"Yesterday afternoon, we collected trace evidence from the first body, and this morning it was sent to the provincial forensic identification center. Results should be available tomorrow."

"Were there any findings from the forensic examination of the scene's surroundings?"

The examination of the scene's surroundings is a standard procedure conducted in every murder case.

The perpetrator is likely to leave behind skin flakes, hair, or other evidence during the act.

Liu Guodong shook his head, "Yesterday we collected a total of 126 pieces of evidence around the scene, and we have already collected fingerprint and DNA samples from all of them."

"Lu Chuan is currently matching the collected fingerprints, but there have been no major discoveries so far."

"This morning, after the incident, we conducted another thorough examination within a kilometer around the scene, collecting 36 pieces of evidence."

"Most of this evidence likely accumulated from yesterday afternoon to now, we aim to process it all today."

Crime scene investigation is not like sweeping; a large-scale search is bound to miss some details.

"Also, we found footprints outside the wall perimeter, and here is the footprint analysis result."

"Oh? It's already completed?"

Qin Yong happily received the footprint analysis report handed over by Liu Guodong.

Liu Guodong nodded, "Lu immediately conducted the footprint analysis upon returning."

"The suspect is an adult male, approximately 184 cm in height, weighing around 100 kilograms, and between the ages of 35 and 40."

Compared to yesterday, when Lu Chuan and others determined the suspect's height to be over 180 cm from the wall's height, the footprint analysis provided more detailed conclusions this time.

"The suspect's footprints show more wear on the outer edge than on the inner edge, though not significantly, indicating the suspect has a slight outward-angled leg type."

In fact, most people's body shapes have some imperfections.

For instance, slightly outward legs, inward legs, or knock knees, commonly known as bow legs.

These leg shapes result from genetic factors as well as external developmental influences.

For example, calcium deficiency or improper walking habits can cause slight skeletal deformities in the lower limbs.

One can analyze the wear pattern on long-worn shoes to determine leg shape.

The information from the crime scene investigation office was still being organized, and Liu Guodong's report temporarily concluded.

Qin Yong turned his eyes to Wang Changjiang, who coughed lightly.

Old Wang was well-rested yesterday. Since the body had not thawed due to being frozen, an autopsy couldn't be performed yet: "The first body is now thawed, and we can perform the autopsy shortly."

"As for the second body..."

Wang Changjiang paused, "An adult female, similar in age to the first body, approximately between 20 to 25 years old."

"The cause of death is mechanical asphyxia, and the size and shape of the neck strangulation marks suggest the same perpetrator as the first body."

Liu Guodong nodded, as he had confirmed this himself.

The neck strangulation marks on both bodies were similarly positioned, thus concluding that the perpetrator's hand size is roughly the same.

Moreover, the perpetrator wore gloves while strangling the victims.

Lu Chuan found no fingerprints on the necks.

"The body had no injuries before death, and no traces of being humiliated before or after death were found for now."

The bloodstains on the snow were a result of the body scraping the wall while being disposed of, damaging the skin and dripping onto the ground.

From the shape, size, and friction mark of the wound, and comparing the remaining bloodstains on the wall, it can be determined that these marks occurred post-mortem.

The wounds inflicted while a person is alive differ from those inflicted post-mortem.

This is because the body has active blood circulation. Injuries sustained before death have a defensive response, known in scientific terms as a life reaction.

This defensive response includes not only active defense by the person being harmed but also the muscle activity response of the injured area.

For example, bleeding, coagulation, muscle spasms, and cellular division during the healing process.

Lu Chuan received a skill card reward in forensic pathology, providing knowledge on distinguishing injuries before and after death.

"We will conduct an autopsy on the first body shortly, and the report will be available tonight. The second body will be examined tomorrow."

...

Crime Scene Investigation Office.

Lu Chuan, who completed the footprint analysis, was comparing the fingerprints found on the evidence collected from the crime scene yesterday.

The advanced fingerprint identification and analysis skill allowed Lu Chuan to quickly process this level of fingerprint comparison.

Processing a single fingerprint took about three to five minutes. After returning from the scene and analyzing the footprints, Lu Chuan completed half of the work.

Yang Sen and Old Bai were handling the evidence brought back from the scene this morning.

"What was the perpetrator thinking, disposing of bodies in the same place twice?"

Old Bai, a seasoned detective, had seen all kinds of cases.

Twenty years ago, the stormy night series murder case, where the perpetrator specifically killed on rainy nights, targeting young women in red riding bicycles.

That year, seven people were killed, causing fear throughout Haizhou City.

In the end, not to mention going out on a rainy day, no woman dared to wear red clothes at all.

Seventeen years ago, the dismemberment case in the South Suburb, the perpetrator killed four people at once, wiping out a whole family. All the bodies were dismembered, put into woven bags, and thrown into sewers, trash bins, and septic tanks.

A total of twelve bags were found, one of which Old Bai found contained four left feet during investigation.

Twelve years ago, the poisoning case, eight years ago, the arson and corpse-burning case...

Old Bai's experience fully demonstrates the saying "you live long enough to see everything."

But this time, the perpetrator disposing bodies continuously at the same location is something Old Bai had never encountered before.

Yang Sen shook his head while scanning the fingerprints, "The perpetrator likely has some deeper reason for doing this."

"Either a psychological disorder, obsessive-compulsive tendencies, or some other compelling reason forced them to do so."

"Normal people wouldn't do such a thing."

Beep, beep!

The two were chatting when the DNA testing machine buzzed nearby.

Yang Sen looked back, "The DNA test results for the second body are in, I'm going to run them through the computer."

Lu Chuan had already collected the fingerprints from the disposal scene of the second body.

Upon returning to the office, the fingerprints were quickly identified and analyzed, but unfortunately, like the first body found yesterday, the fingerprint comparison was unsuccessful.

There was no target person in Haizhou City's Criminal Investigation Team fingerprint system.

Facial recognition against the missing persons database also yielded no matching information.

Logically, in such cases, DNA information comparison is also unlikely to succeed.

Since 90% of DNA database entries in Haizhou City's Criminal Investigation Team also have fingerprint records.

If fingerprints didn't match, it's improbable that DNA comparison would succeed either.

However, there's a reason for each step in criminal investigation procedures.

Ding!

Just as Yang Sen had entered the DNA information of the second body into the system and begun comparison, the computer chimed with a successful match notification!

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