Just as Sang Ning was about to take out an evidence bag, the man beside her silently handed one over first.

She quickly slipped the thin cotton thread inside and sealed it.

“No wonder I didn’t hear a single sound last night,” she said quietly.

Gu Yezhou frowned slightly. “Estimated time of death?”

Sang Ning pointed at the stains on the victim’s pants, feet, and wrists.

“When the body’s muscles relax completely, the sphincter loses control—what we commonly call incontinence. That’s why this happens.”

She pressed lightly around the body as she continued.

“The face is cyanotic. Rigor mortis has spread throughout the body. I’d estimate about ten to twelve hours.”

She glanced at her watch.

“It’s 4:10 p.m. now. That means the victim likely died sometime between six and eight this morning.”

“If the death occurred in the morning,” Gu Yezhou asked, “why did you say you didn’t hear anything last night?”

Sang Ning looked at him steadily.

“Because the victim’s death process would have taken a long time. If the killer came here around three or four in the morning, there are only three possible ways they could have entered: one, knocking on the door; two, picking the lock; three, climbing in through the window.

“We live on the second floor. But no matter which method they used, it would’ve caused a fair amount of noise.”

She paused.

“Captain Gu might not know this, but Ping’an Apartments has terrible soundproofing. Even the smallest noise echoes through the halls. That’s exactly what puzzles me.”

Gu Yezhou nodded thoughtfully.

“Could it be that you were unusually tired last night and slept too deeply to notice?”

Sang Ning shook her head.

“No. There’s something else you might not know about this place. Ping’an Apartments has a reputation. People call it the ‘Hell Apartments.’ Supposedly it’s haunted. People die here fairly often.

“I only rented here because it’s cheap.”

She continued calmly,

“So my sleep is very light. Any little sound wakes me up—even the creak of a loose window.”

Sang Ning had been blind shortly after birth.

Because of that, her other senses had developed far beyond those of an average person.

But that past was something she never liked to talk about.

She had spent eighteen years trembling through life in a rural village—locked in a cage, treated worse than an animal.

Even now, she still tried to remember where that village had been.

Every night in her dreams, all she saw was endless darkness… accompanied by those sharp, biting voices and their constant mockery.

“If you’re such a light sleeper,” Gu Yezhou said slowly, “and you didn’t hear anything at all… could you have taken sleeping pills? From what you said earlier, your sleep isn’t great. Have you ever thought about improving it?”

For some reason, hearing her story made his chest feel strangely tight.

Sang Ning’s salary wasn’t low.

If saving money was her goal, she still didn’t need to live in a place like this.

Unless there was another reason.

“No…” Sang Ning crouched down, staring absentmindedly at the rope marks around the victim’s limbs.

Following her gaze, Gu Yezhou crouched beside her.

He lifted the knot tying the rope and examined it carefully.

“This is a climbing knot. Do you know anyone close to the victim who’s into mountaineering?”

“No.” Sang Ning answered without hesitation.

She recognized the knot immediately.

And the moment she saw it, someone’s face had surfaced in her mind.

Gu Yezhou noticed the change in her expression.

“You know someone?”

Sang Ning looked up at him. Beneath her mask, her teeth pressed tightly against her lip.

“I… might know who the killer is.”

“So soon?” Xiao Zhang exclaimed in shock, though excitement quickly followed. “Who is it, Dr. Sang? Someone you know?”

Sang Ning shook her head.

“It’s only a guess. I can’t be certain. The victim didn’t know any climbers—but I do.”

“What does that mean?” Xiao Zhang frowned. “You’re not saying your friend killed your neighbor, are you? They had no grudges—why would someone kill your neighbor?”

“Yes… why?” Sang Ning murmured.

She looked at Gu Yezhou.

“Can we move the body back first? I need to conduct a more detailed examination.”

Seeing she didn’t want to say more, Gu Yezhou didn’t press the issue.

“Alright. But could I get a copy of the surveillance footage outside your door?”

He walked toward the hallway and pointed to the camera mounted outside Room 203.

Sang Ning nodded.

“I checked it on my way here. The killer doesn’t appear on it. They probably didn’t use the eastern staircase.”

“Got it.”

Gu Yezhou stepped back into the apartment.

When he had first arrived at Ping’an Apartments, he’d honestly wondered if he had come to the wrong place.

Aside from a traffic camera at the intersection two hundred meters down the road, the entire complex had no security.

No guards.

Not even a single surveillance camera inside.

There were no cameras on the stairwells either.

The walls were peeling and stained. Water damage spread across the ceilings. The building looked half-abandoned, still connected to water and electricity only because the developers hadn’t completely given up on it.

“We didn’t find any signs of a struggle,” Xiao Zhang reported while following behind him. “No fingerprints either. The place was cleaned very thoroughly. Also, all valuables in the victim’s home are missing. It’s very likely a robbery-murder case.”

He paused, then asked toward the doorway:

“By the way, Dr. Sang—did the victim have a girlfriend or anything? Did you know about it?”

Sang Ning was still standing where she had been, replaying everything that had happened the night before.

When Xiao Zhang repeated himself, she shook her head.

“As far as I know, he didn’t have a girlfriend. He was a shut-in. Very small social circle. Mostly stayed at home.”

Inside the bedroom, Gu Yezhou listened to her explanation.

Then he looked at the contents of the wardrobe.

And fell silent.

“Well, that’s strange,” Xiao Zhang muttered as he walked in. “No girlfriend, but there’s this many bras in the closet—and some of them even smell used. Don’t tell me the victim was some kind of underwear thief.”

The words *underwear thief* made Sang Ning’s heart skip a beat.

She hurried into the bedroom.

Just as she stepped inside, she nearly collided with Gu Yezhou, who was placing the bras into an evidence bag.

Her eyes instantly locked onto the bag.

Her pupils shrank.

Even through the thin mask covering her face, Gu Yezhou could clearly see the shock written across her expression.

He stood still and asked nothing.

He would wait for her to speak first.

A suspicion had already formed in his mind.

But he hoped he was wrong.

If the killer turned out to be Sang Ning’s friend… what would she do?

Would she cover for them?

Sang Ning turned her head toward the bedroom window.

Then she noticed the long clothes-drying pole leaning beside it.

At that moment, everything clicked into place.

She took the evidence bag from Gu Yezhou’s hand, drew in a deep breath, and said:

“There’s no need to test these.”

She held up the bag.

“The underwear here… all belong to me.”

“What?!”

Xiao Zhang had been combing through the scene again and again, afraid of missing anything. He was in the bathroom checking for traces when he heard her say that.

His voice shot up instantly, loud enough to attract the attention of Old Chen from the technical team nearby.

“Xiao Chen! If you’ve got nothing useful to do, just get out already! Can you stop messing around in here? You’re an investigator—why aren’t you out there questioning the neighbors instead of crowding the crime scene?”