The Forensic Doctor Better Than a Detective

”Exactly.” Director Hou nodded as well. ”We’ve found traces of male assault on the victim’s body, but whether there are actually male components inside her body still has to be confirmed by laboratory tests.”

Hearing their suggestion, Mr. Chen didn’t extend the dinner invitation again.

After all, before the case has a clear direction, everyone’s mood is pretty heavy.

Even the finest delicacies right in front of them wouldn’t stir their appetite.

As they spoke, the vehicle sped off into the night.

Forty minutes later, the five of them returned to the Guangling City Public Security Bureau.

After getting out of the car, they went straight to the forensic evidence lab without a moment’s delay.

At that moment, the on‑duty examiner was already waiting at the door. He took the evidence and immediately began the testing.

Chen Guan, Director Hou, and Jiang An stood outside the observation window, watching the examiner work step by step.

Extraction, amplification, adding reagents, putting it into the instrument for purification...

Right now, the three of them all had a strong sense of expectation written on their faces.

They all knew how crucial this test result was to the case.

If the comparison matched, everyone would be overjoyed and could relax over late‑night snacks and drinks.

But if there was no match, there would still be a lot of work ahead.

Twenty minutes later, Vice Director Chen turned and said, ”Director Hou, Mr. Jiang, why don’t we wait for the results in the conference room?”

Director Hou waved his hand. ”Forget it, we’ll just sit here in the lab for a bit.”

As he spoke, he glanced at the chairs behind them. ”We’d just be waiting downstairs anyway. Might as well wait for the result here; it shouldn’t be long.”

Vice Director Chen quickly said, ”Alright then. But since this is a sterile lab, we can’t have tea in here.”

”Once the results are out, we’ll clock off and I’ll make you some of my private stash of good tea.”

Then the three of them waited nearly another thirty minutes.

Suddenly, the on‑duty staffer in a lab coat came out holding the electropherogram. ”Mr. Chen, the results are out.”

”How is it?”

”From the evidence extracted from inside the female, apart from the victim’s own DNA, we didn’t find components from a second person.”

”Any semen stains or prostatic fluid?”

Jiang An asked.

”No. I did a preliminary test—no prostatic components.”

Hearing this, both Director Hou and Chen Guan looked visibly disappointed.

They had been full of hope for this result; the outcome was truly unexpected.

The victim’s face, chest, and lower body all had large areas of biting and tearing, which clearly indicates a very strong sexual drive.

But the lab result had dealt them a heavy blow.

Next, Director Hou asked, ”Is it possible the killer used a condom, took protective measures?”

Hearing this, the examiner opposite them said helplessly, ”That I can’t determine.”

”Our lab can only test whether male components are present.”

”If you want to determine that issue, you’d have to send it to the micro‑trace evidence section of the physico‑chemical lab.”

At that, Jiang An raised his hand and waved. ”Thanks for your hard work. You can get back to it.”

Then he turned and said, ”Alright, I’ll call the Jiangcheng lab and have them stand by.”

”Please have Mr. Chen arrange for someone to send the evidence to Jiangcheng for micro‑trace evidence testing.”

Chen Guan smiled and said, ”Then I’ll trouble you with that, Mr. Jiang.”

”It’s no trouble. We’re all brother units, and it’s all for solving the case.”

But at this moment, Director Hou’s brow was tightly furrowed.

He said, ”If we send the evidence to Jiangcheng and they still can’t get a result, what are we supposed to do then?”

Criminal investigation is all about bold hypotheses and cautious verification.

So neither Jiang An nor Chen Guan was surprised by his question.

But for a moment, Chen Guan didn’t know how to answer.

Jiang An thought for a bit and said, ”Director Hou, what you’re talking about is exactly what I was thinking just now.”

”If even after micro‑trace testing we still can’t detect trace components from male protective measures, then there are only two possibilities.”

”Which two?”

”One possibility is that the killer never actually penetrated her, only assaulted her externally.”

”The other possibility is that there was slight contact, but not deep.”

”While the body was drifting in the water, the water pressure would cause a small amount of water to enter the victim’s body.”

”In that situation, any trace micro‑evidence remaining inside would be washed away by the water.”

”Under those conditions, with the precision of our current instruments, it can’t be detected.”

Hearing Jiang An’s explanation, the two men opposite him nodded repeatedly. ”Right, that explanation is very reasonable.”

Then Jiang An went on, ”But regardless of whether we detect male components or condom residues inside the victim, I don’t think it can cover up one fact.”

”Oh? Go on.”

Mr. Chen asked at once.

Jiang An analyzed, ”There’s one very crucial point in this case.”

”The parts of this female victim’s body that were assaulted by the male are numerous—her lips, chest, lower body—and the local pattern of assault is extremely intense.”

”According to normal reasoning, there’s a major contradiction here.”

”A contradiction?”

Jiang An said, ”If we compare things, based on the surface injuries we can judge that the killer’s sexual intent was very strong.”

”But why is there no male trace whatsoever inside the victim’s body?”

As soon as he finished, Director Hou analyzed, ”Could it be because the victim was on her period?”

”Which forced the killer to give up, or made him abandon the idea of penetration.”

He then recalled, ”I’ve handled a case before where, during the assault, the suspect saw the woman’s menstrual blood and felt extremely disgusted, then gave up the idea of further assault.”

As soon as he said this, Mr. Chen quickly nodded in agreement. ”Exactly!”

”Back when I was a criminal investigation team leader here in Guangling, we had a case just like that. I still remember it clearly.”

”In that case, the victim’s body surface showed signs of sexual assault, but internal testing was negative.”

”I remember when we caught the killer, he said that when he saw a lot of blood on the victim’s underwear, he felt extremely disgusted and gave up the idea of further assault.”

”In this case, could the killer be thinking the same way?”

When he finished, the two of them looked over at Jiang An in unison.

The corner of Jiang An’s mouth twitched. ”Director Hou, Mr. Chen, what you’re describing does happen.”

”Some offenders do terminate the crime because of a woman’s menstruation. But in this case there’s something very particular.”

”I don’t know if you recall this: when we did Scene Investigation in the bathroom, we didn’t find any sign of menstruation.”

Once he said this, Chen Guan and Director Hou immediately began recalling the bathroom scene.

Then Jiang An continued, ”Neither on the victim’s removed underwear, nor in the bathroom trash can, did we find any red stains.”

”And we only found out she was menstruating by cutting open her uterus.”

”I even noted during autopsy that there was no obvious blood in the vaginal canal.”

”On the night of the crime, the victim was likely at the very onset of her period.”

”During her struggle before death, the sudden surge of intra‑abdominal pressure and increased vascular pressure caused tiny uterine vessels to rupture, and a small amount of blood to enter the uterine cavity earlier than usual.”

Finally, Jiang An concluded, ”So I have reason to believe that when the victim was killed, the killer did not know she was on her period.”

Hearing Jiang An’s analysis, Mr. Chen and Director Hou were momentarily stunned.

After a long pause, they both said, ”If he didn’t know she was menstruating at the time, why didn’t the killer go on to commit the crime further?”