Controlled Experiment Chapter 6

Controlled Experiment – 6

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Xiao Bai was woken up by his phone.

He picked it up and glanced at the screen. Three-thirty in the morning.

Last night, he'd been thoroughly scolded by Du Yusheng. After getting it off his chest, Du Yusheng felt refreshed, while Xiao Bai had been left unable to sleep. In a daze, he hadn't fallen asleep until around one or two in the morning, and now, barely two hours later, he'd been woken up again by this call.

He looked at the screen, it was Du Yusheng again.

Xiao Bai thought it was bizarre. Did this man never sleep? Is he part owl or something?

He cursed inwardly, but his tone remained pleasant and respectful.

"Brother Yu, something wrong?"

From the sound of car horns in the background, it seemed Du Yusheng was still on the road.

"One thing, I just saw a key at Li Yao's place that looks like it belongs to Luo Daheng's villa, look into his assets and bank accounts."

"... Brother Yu, it's three in the morning," Xiao Bai reminded him.

Du Yusheng chuckled on the other end. "Exactly, it's only three, just get it to me by the time you start work at eight, I'm not in a rush."

Xiao Bai was nearly laughing from anger. "Brother Yu, you really do care for your subordinates."

It was meant sarcastically, but who knew? Du Yusheng laughed heartily and said, "As I should, as I should."

Xiao Bai couldn't even bring himself to laugh anymore. He hung up and cursed, Care my ass.

Lucky him, saddled with someone who must have been an owl in his previous life.

On the morning of the third day after the incident, Du Yusheng had his feet propped up on the coffee table and let out a long sigh.

There was still something that didn't quite make sense to him.

While he was brewing a second pot of tea, Xiao Bai burst in from outside, dripping with sweat.

"Brother Yu, about what you said on the phone that day at the hospital, they looked into it. The housekeeper really did go to the pharmacy that night, and they found the receipt from that shopping trip in his garbage bin at home. He bought the exact same cold medicine that Luo Daheng had taken before his death. They also found that bottle at his place."

Xiao Bai wiped the sweat running down his face.

He narrowed his eyes and squinted at Xiao Bai, "The housekeeper was that careless? He didn't even get rid of the receipt?"

Xiao Bai nodded. "They also looked into the distribution of Luo Daheng's assets before his death, Mrs Luo only got five per cent. Moreover, they found a copy of that distribution document in the housekeeper's house."

Five per cent?

"... That's damn harsh, she shared a bed with him for years and only got five per cent in the end. That's cold." Shaking his head, Du Yusheng asked, "Aside from Mrs Luo... who got the majority of it?"

Xiao Bai flipped through the documents in his hand. "Aside from what went to charity, the bulk of it went to his illegitimate son, Luo Yang."

Luo Yang? Du Yusheng remembered that on the night Luo Daheng died, Luo Yang had come to see him too.

"Is Mrs Luo aware of this asset declaration?"

Xiao Bai shook his head. "Luo Daheng's lawyer said that apart from Luo Daheng himself, no one knew about it."

"Then how did the housekeeper find out?" Du Yusheng stroked his chin, piecing together a thread in his mind.

The housekeeper somehow found out about Mrs Luo's share of the inheritance. Holding resentment in his heart, and given his complicated relationship with Mrs Luo, he likely had long been displeased with Luo Daheng in daily life. So, he went to the pharmacy to buy the medicine and used the convenience of his position to secretly swap out Luo Daheng's nitroglycerin.

"... But Luo Daheng died from an overdose," Qin Yan interjected. "Isn't that a contradiction?"

Du Yusheng snorted and waved a hand lazily.

"We'll figure it out during interrogation." He tilted his head and looked at Xiao Bai. "Have they brought him in yet?"

Du Yusheng sent Xiao Bai off to interrogate the man and sat in his office in a daze.

After going home last night, his head had been a mess, like a reel of film spinning wildly. Du Yusheng felt exhausted and slumped lifelessly on the sofa, his mind blank. For some reason, something in his brain suddenly connected, and Du Yusheng thought of someone again.

Li Yao.

There was something odd about that man. From the very first glance, Du Yusheng felt he was hiding something. That impression only deepened after questioning him.

It wasn't a baseless suspicion. To know that nitroglycerin could kill as well as heal, besides Luo Daheng, who took it regularly, one would need at least some medical background. Then there was that slip of paper with the words "controlled experiment" written on it. Du Yusheng had examined it, it wasn't a standard size, it had to have been cut down. And the way it had been trimmed was meticulous: the edges straight as a ruler, not a single paper fibre or ragged edge in sight. Even more, the square had been folded with perfect symmetry. From that, Du Yusheng concluded that the person was fastidious, careful, and disciplined in everyday life. Following that line of thought, it increasingly pointed to Li Yao being suspicious. And yet, the man shielded himself with lies so well-crafted they couldn't be easily dismantled.

It was like he had "I'm hiding something, come investigate me" written across his face.

"... Do you think the housekeeper is the killer?"

The sudden question in the quiet office caught Du Yusheng off guard, he only now realised Qin Yan was still there.

Du Yusheng shifted into a more comfortable position and shook his head.

"He doesn't look smart enough," he said. "He doesn't even know how to handle a receipt..."

Qin Yan nodded. "So what do you think now?"

Du Yusheng's foot which had been resting on the coffee table finally landed on the floor. The tea in his cup had long gone cold, but he still held it, watching the whirlpool form as he swirled the liquid. Qin Yan reached over, gripped his wrist, and topped it up with hot water.

"There's one thing I still can't figure out," Du Yusheng put the teacup aside. "Like I said before, the three people he saw before his death were all separated from the time of his death by too large a gap. If one of those three had harmed him, why did it take so long for the symptoms to occur? So I think it could only have been Luo Daheng who took the medicine himself. Then why would he poison himself? There's only one reason, Luo Daheng didn't know what he was taking."

Qin Yan stroked his chin.

"So the key point now is how the killer managed to do it."

Du Yusheng nodded and voiced another of his suspicions. "And there's a very good chance the killer wasn't acting alone."

It was nearly two in the afternoon by the time Xiao Bai emerged from the interrogation room. There were beads of sweat on his forehead. He'd only just been transferred up from below, not entirely green, but still understandably nervous.

"The housekeeper admitted to having an affair with Mrs Luo," Xiao Bai reported. "He also admitted to swapping out Luo Daheng's cold medicine before he died. He was just dissatisfied with the five per cent Luo Daheng left her. He's not the brightest of minds, so he came up with this idiotic plan. But he didn't admit to the nitroglycerin overdose. From the looks of it, he genuinely didn't know it could be fatal."

Just as Du Yusheng had suspected.

"He's been set up."

Xiao Bai nodded. "He also revealed one more lead. That illegitimate son, Luo Yang, had a poor relationship with Luo Daheng. He was always coming around asking his father for money, and they'd end up arguing every time they were together. Seemed like he was quite ungrateful. The housekeeper kept calling him an ungrateful brat during the interrogation. What I don't get is, if he disliked him so much, why give him such a large share?"

Disliked him, yet still left him money.

Du Yusheng suddenly thought of himself. Old Master Du had never liked the way he looked, every time they met, he scolded him. But somehow, his pocket money never ran dry. Could it be that Luo Daheng had been a loving father too?

"Where's this Luo Yang now?"

Xiao Bai replied, "He flew abroad right after seeing Luo Daheng that day, apparently to handle some business on his father's behalf. Now that he knows his father's dead, he's on his way back."

Du Yusheng chuckled. "He'll return a billionaire." Then, after thinking about it, he added, "What about Li Yao? Did you ask about him?"

Xiao Bai nodded. "The housekeeper said Li Yao is a very responsible doctor who doesn't talk much. Aside from his usual duties, you'd rarely hear a word from him." Knowing Du Yusheng would ask more questions, Xiao Bai quickly added, "I'm still checking Li Yao's bank records, should have results soon."

"Good." Du Yusheng gave Xiao Bai instructions: "Take a few people and keep a close eye on that Luo Yang. As soon as he's back, find a chance to question him, see how he reacts."

Just before the end of the workday, Du Yusheng went to the forensic office, intending to bring Qin Yan back for a discussion on the case. But when he got there, he realised Qin Yan was already off duty.

Qin Yan's forensic office was also known as the bureau's morgue. The moment one stepped inside, a chilly draft pierced straight through the chest. Even though Du Yusheng mentally prepared himself beforehand, he was still startled by the array of specimens lined up on the adjacent shelf when he switched on the lights. Sometimes Du Yusheng couldn't help but wonder, Qin Yan keeps these things on his dining table, isn't he afraid that one day he'll mix them up while eating?

Inside one of the drawers were a few photos of Luo Daheng's autopsy. Du Yusheng took them out and flipped through them.

Sometimes it seemed like Qin Yan was collecting stamps the way he put even the most broken and torn things into the drawer.

When he got to the last two photos, Du Yusheng stopped.

They were of Luo Daheng's thumbs.

Du Yusheng remembered that at the crime scene, there had been a black, soot-like substance on Luo Daheng's thumb, possibly carbon powder.

That carbon powder still didn't quite make sense to Du Yusheng. Could it really have been transferred from the label when Luo Daheng gripped the nitroglycerin bottle tightly in his final moments?

Since Qin Yan had already left for the day, Du Yusheng decided not to call him back. The Luo Daheng case didn't warrant tying everyone up at this hour.

When he left the bureau, the sky outside was already dark. Once deep autumn set in, night fell quickly. Du Yusheng looked up at the stars, sniffled, and headed towards the underground parking garage where his car was parked. He didn't drive often, sometimes when his temper flared, everyone annoyed him, and he preferred racing taxis instead. Whenever a car stopped at a red light, Du Yusheng liked to surge ahead and overtake them just for the thrill.

He buckled his seatbelt and was just about to start the engine when his phone rang.

Du Yusheng glanced down, it was his dear mother calling.

There was one redeeming quality about him: he was filial.

He answered without hesitation and was immediately met with a tirade of nagging from his mother, the usual lines about how long it had been since he last came home. Not daring to talk back, Du Yusheng kept his head down and answered with a series of hums and mumbled acknowledgements.

But after all, he was her own flesh and blood. After a few more scoldings, Madam Du's anger gradually subsided.

"What do you want to eat this weekend, I'll have someone make it for you."

The old lady's sudden change of tone caught him off guard. Du Yusheng rubbed the seatbelt back and forth with his fingers, unable to utter a single word.

From the other end, Madam Du laughed coldly. "Doesn't react even when hit. I'll just have them sort it."

"Ah, alright."

It was rare to see a timid side to Du Yusheng.

Just before hanging up, Du Yusheng called out to the old lady.

"Erm... I'm the only son in our family, right?" After thinking about it, Du Yusheng added, "We don't have any of those family drama-type situations where a long-lost brother or something turns up halfway, right?"

"I say, Du Yusheng, what are you thinking about for no reason?" The old lady sounded as if she were playing mahjong, just as she said that, the sound of someone winning a hand came through the phone. "Your father and I are at this age, are you seriously expecting us to give you a younger sibling now?"

"No, no," Du Yusheng shook his head quickly. "There's not enough money to go around, forget it."

After hanging up, Du Yusheng finally had some peace and quiet in his ears.

The old lady's affectionate scolding had a way of jolting him sober. Du Yusheng's foggy brain felt much clearer. He opened the navigation app to check the traffic. The main road was being repaired today, and the eastern route was congested. With no other choice, he had to take a longer detour.

He thought that taking the longer route might offer a bit of peace, but the traffic turned out to be just as bad. The delay was twice what it normally would have been.

Old Master Du's home was the first house at the start of the lane. As Du Yusheng passed by, he hurriedly stepped on the accelerator, afraid his mother might spot him through the window and come charging out to scold him in front of all the wealthy ladies.

The area around Luo Daheng's villa had been cordoned off with police tape. The car headlights lit it up from a distance with a faint green glow. There was no place to park there, so Du Yusheng had to leave his car up ahead and walk over. As he was parking, he noticed a white Bentley parked beside him. Scratching his head, Du Yusheng stared at the vehicle in a daze.

People's living standards really were rising, no wonder the news kept reporting on GDP climbing sky-high. Since he drove in, how many Bentleys had he seen already?

As luck would have it, someone was inside the Bentley. While Du Yusheng was still standing nearby, he saw Li Yao step out of the car.

He wore a long dark overcoat, which accentuated his tall frame. The coat hung open naturally, revealing a plain white T-shirt underneath. Li Yao's style was simple, without any unnecessary flair, yet it was pleasing to the eye. As if he had forgotten something, Du Yusheng watched as he took a few books out of the car.

"Yo, Dr Li?"

Li Yao turned instinctively at the sound of his name.

Du Yusheng stood straight beside his own car, smiling at him.

At that moment, Du Yusheng was a little annoyed, he should have brought his Porsche. Parked next to a Bentley, his ten-times-refurbished old banger looked utterly lacking in presence.

Sure enough, Li Yao glanced in his direction.

"Vice-captain Du's car really is unique."

A little embarrassed, Du Yusheng scratched his head and hurriedly explained, "... It’s too easy to blend in, this way, it’s easy to recognise."

Li Yao smiled with pressed lips. "It's easy to spot."

The black body of the car had a grey door. The lights on either side didn't match, so Du Yusheng coloured them orange with a marker to pass them off as a pair. Fortunately, he rarely turned both lights on at once. It wasn't anything particularly conspicuous, yet Li Yao's gaze lingered on the headlights of his car.

Du Yusheng cleared his throat, "It's so late, what brings you here, Dr Li? Whose private physician are you this time?"

Li Yao shook his head. "No one's. I still have a few things here that I haven't finished moving."

"Moving?"

Du Yusheng felt his head starting to buzz. Last night, he indeed heard Li Yao say that he had just moved into that neighbourhood not long ago.

"... You used to live here?"

"Not exactly, I didn't come often," Li Yao thought for a moment. "I only come a few times a year, so I decided to move everything over this time."

A small doctor who drove a Bentley and could afford a villa.

Du Yusheng laughed coldly. "The late Luo Daheng lived in this neighbourhood too."

Li Yao didn't look the least bit offended. He lifted his head slightly.

"I heard Vice-captain Du's father lives around here as well."

It was a blunt knife, and Du Yusheng got another layer of understanding about him.

Li Yao held two books in his hands, several pages of which had been marked.

"May I have a look at the books in your hand?"

Li Yao looked over at Du Yusheng. "In what capacity? As a police officer?"

"If that's how you want to see it, so be it."

Li Yao didn't refuse. He handed the books to Du Yusheng.

In truth, Du Yusheng couldn't understand medical textbooks, the terminology was long and difficult to pronounce, he'd come across it before when reading things at Qin Yan's place. Li Yao's books had very few notes, with almost no annotations. The pages that were marked were easy to spot: clinical applications of nitroglycerin.

Lifting his head, Du Yusheng looked at Li Yao. "That night, what exactly did you do?"

Li Yao sighed. "I'd rather not repeat what I've already said at the station."

"Then do you know Luo Yang?"

Li Yao thought for a moment, "He was Luo Daheng's illegitimate son. I've met him a few times, but I don't know much about Mr Luo's private affairs. However, something has just come to mind, I'm not sure if it'll help you. Mr Luo's asthma has been particularly severe these past few months."

"How severe?"

"Severe enough that inhaling a large amount of dust in a short time could trigger an attack." Li Yao let out a barely audible sigh. "Vice-captain Du, I have nothing to do with Mr Luo's case. It's okay to break into my home, pry into my words, and investigate me, but just know this: if you focus all your energy on me, you'll get nowhere."

Suddenly, Du Yusheng smiled.

"I sincerely hope this matter has nothing to do with you."

Under the light, Du Yusheng saw a hint of disbelief in Li Yao's usually calm eyes. With his head lowered, a slight smile tugged at the corner of his lips. Du Yusheng had told many lies in his life, spun all kinds of stories. But this sentence, had come from the heart.

‿︵‿︵ʚ˚̣̣̣͙ɞ・❉・ ʚ˚̣̣̣͙ɞ‿︵‿︵

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Translator Notes

Please feel free to comment any mistakes I made so I can improve and do better as I go through the book.

Translated: May 14, 2025 by Angel

Edited: June 3, 2025 by Angel