I Play Dungeons in the Police Station-Chapter 232 - 162: Luminol Reagent

Qiao Baoshan clearly wasn’t the ruthless type. When faced with the police investigation, from the moment he nervously offered cigarettes, it was evident he was feeling guilty.

But, just from this, it couldn’t be concluded that he was a suspect.

Evidence was still needed.

After entering the house, Ding Youqiang began asking, "You said that night you went eel fishing with your dad?"

"Yes."

"What shoes did you wear that day?"

Generally, catching eels is done by the riverside or in a paddy field. If he really went eel fishing, his shoes would be muddy, and simply checking the soles and the sides of his shoes would reveal whether he was lying.

Qiao Baoshan was taken aback; he didn’t expect the police to ask such detailed questions. So he had to follow along, "I washed the shoes; they were too dirty, all muddy. I washed them the next day."

"Oh? Is that so? Then what about the clothes you wore that day? They should have been quite muddy too, right?"

"Yes, yes, I wore a white tank top, and it was dirty too, so I washed it with the shoes."

When Ding Youqiang heard about the white tank top, he knew Qiao Baoshan was lying, so he asked further, "Really? But I heard from Qiao Liangfu that when you played cards that day, you were in black clothes?"

"It was too hot, so I took a shower when I got back and changed my clothes."

"Didn’t you need a shower after going eel fishing anyway?"

"The eel fishing was on a whim; my dad said he wanted to go, so I thought I’d accompany him."

In this back-and-forth, Qiao Baoshan’s thinking time increased, especially when Ding Youqiang pointed out some details; to cover up, he had to fabricate more. 𝒻𝘳𝘦𝘦𝘸ℯ𝒷𝘯𝘰𝑣ℯ𝑙.𝘤𝑜𝘮

Seeing this, Li Xiang was now almost certain it was him, but still, evidence was needed.

The law requires evidence. Without it, even if you know he is the murderer, you can’t punish him.

Li Xiang, hearing Ding Youqiang mention the black clothes Qiao Baoshan wore that day, chimed in, "Those black clothes should still be around, right?"

As Li Xiang spoke, Qiao Baoshan glanced at him, seeing he was young, and didn’t take him seriously, casually answering, "Yes, still here."

"Good, could you please bring them for us to see?"

"What’s there to see about some worn-out clothes~"

"Stop wasting time, Team Leader Li asked you to bring them, so do it."

Ding Youqiang noticed Qiao Baoshan was being somewhat disrespectful to Li Xiang and scolded him. Qiao Baoshan, somewhat afraid of this criminal police captain, turned back into the house to get the clothes without daring to say more when he saw Ding Youqiang angry.

Seeing Qiao Baoshan go back to fetch the clothes, Ding Youqiang asked softly, "Is there something wrong with the clothes?"

"Yes, I examined the blood stains at the scene and, based on the splatter range, I believe a small part of the blood got on his clothes. Did you bring the Luminol Reagent?"

Luminol, typically a pale yellow crystal at room temperature, is often combined with hydroxide to identify blood.

The principle is as follows: iron in hemoglobin decomposes the hydroxide into water and oxygen, which then oxidizes the Luminol to emit a blue-white glow.

This solution is now widely used in criminal investigation techniques due to its high sensitivity, detecting blood as diluted as one part per million.

"Yes, we brought it."

Ding Youqiang understood Li Xiang’s meaning, so he signaled a technical officer, who brought a bottle of Luminol Reagent spray.

It’s generally convenient this way. Wherever blood is suspected, spray it, and if it glows, it confirms the presence of blood.

However, it’s not foolproof.

Luminol also glows in the presence of iron, iron alloys, horseradish, or certain bleaches, and it can detect animal blood, so confirming human blood requires DNA testing.

Fortunately, the Luminol Reagent doesn’t adversely affect the blood, allowing for subsequent DNA testing.

"Here, it’s these clothes and I’ve washed them."

"No problem if they’re washed, let’s go inside."

Ding Youqiang took the black T-shirt Qiao Baoshan handed over and scrutinized it.

Since the shirt was black and washed, he couldn’t see anything directly.

So he took the shirt inside, pulled out the Luminol Reagent spray, and sprayed it on the shirt.

Soon, the spots where the chemical solvent was sprayed emitted a bright blue glow.

Even in daylight, the approximate bloodstain range was clearly visible.

"Oh my, the gods have shown themselves, my shirt is glowing!"

Witnessing this phenomenon for the first time, Qiao Baoshan was astonished, believing it to be a divine sign.

"This solution is called Luminol Reagent. It glows blue-white when it encounters blood."

With village folk often mistaking science for the divine, Li Xiang offered this explanation.

Upon hearing Li Xiang, Qiao Baoshan’s expression altered drastically, incredulously saying, "Impossible, I washed this shirt. You’re framing me."

"Luminol is highly sensitive to blood. Even if you’ve washed it, trace blood residues too minute to be seen linger on your clothing. It can detect blood diluted to one part per million."

The blue glow lasted about half a minute, sufficient time for the technical officer Ding Youqiang had brought to photograph and document the evidence.

Hearing Li Xiang’s words, Qiao Baoshan collapsed onto the ground.

His mother, seeing the situation, hurriedly ran over, embracing him and asking worriedly, "Son, what’s wrong? Are you hurt?"

"Mom, I’m sorry. I killed Qin Qinglian."

"What? Why did you do something so foolish? Why kill her?" Hearing her son’s words struck the old lady like a thunderbolt, leaving her stunned.

In her view, though her son was lazy, gambling a bit here and there, she never imagined he could kill someone.

"I didn’t want to; I just wanted to steal some money for fun. She suddenly appeared, saying she’d report me. I had no choice. I had no choice!"

The mother and son clung to each other, crying bitterly. The intense emotional bond between them might lead onlookers to speculate about police mistreatment.

"Qiao Baoshan, you’ll need to come with us to the station for further investigation."

Now that the truth was revealed, Ding Youqiang could finally breathe a sigh of relief and give the public an explanation.

"Son, with your father gone and now you being taken away, how am I supposed to live?"

Watching the departing police car, the old lady knelt at the doorway, crying to the heavens.

The interrogation of Qiao Baoshan went unusually smoothly, and he revealed where he had disposed of the murder weapon.

The police found the fruit knife he used at the reported location after a half-hour search.

This knife was from Qin Qinglian’s own home.

In reality, the incident’s root cause was simple: Qiao Baoshan and his group, frequently playing cards at Qin Qinglian’s shop, faced constant financial difficulties. His aging father had supported him, but finances were always tight.

Seeing Qin Qinglian often handle money and stash it in a drawer, the idea of theft came to him.

To avoid police detection, he even wore gloves.

On the night of the crime, Qiao Baoshan played cards at the shop. After losing his money, he didn’t return home, opting instead to hang around, waiting for the game’s end, hiding in the bathroom as Qin Qinglian closed up, planning to steal after she left.

Unfortunately, halfway through his theft, Qin Qinglian came back, saw him, and began shouting she’d report him to the police.

Afraid his plot would be exposed, in panic, Qiao Baoshan noticed a fruit knife on the counter that Qin Qinglian often used and, out of desperation, picked it up and stabbed her.

His mind went blank; fearing one stab wouldn’t suffice, he stabbed a few more times, getting blood on his body and face until she no longer moved. Only then did he realize the gravity of his actions and hurried home.