Serial crimes are often premeditated. Perpetrators typically prefer to operate in familiar areas, adhering to the "three-no" principle.

Not too far, not too close, and no repeat locations.

Not too far means the perpetrator generally won’t commit crimes in distant places, especially those they are unfamiliar with. This stems from a psychological need for a sense of security.

Not too close is also easy to understand. Committing a crime right on one’s doorstep is high-risk, as it’s easy to run into acquaintances. As the saying goes, "A rabbit doesn’t eat the grass around its own burrow."

No repeat locations means the crimes will not occur in the same place. Any location where a murder has occurred will have heightened security, and the public will be more vigilant, increasing the risk for the perpetrator.

The five crime scenes on the map formed a pentagram. In the empty space at the center of the intersecting lines, Zhao Lin saw a familiar name: Yunlai Inn.

"Isn’t this the inn from the locked-room murder case?"

Zhao Lin’s mouth hung open in surprise as he recalled the bizarre case.

At the beginning of this year, a traveling merchant with an out-of-town accent checked into the Yunlai Inn near the docks.

The merchant claimed to be a jade seller from the Wanli Jade Shop in the provincial capital.

He stayed at the inn for a full fortnight, running around the city every day with his jades, trying to drum up business.

One morning, an attendant came to the merchant’s room to deliver hot water. He knocked for a long time, but no one answered.

The attendant found it strange. ’This merchant always gets up so early. What’s different today?’

The attendant assumed the merchant was sleeping in and didn’t think much of it. But when evening came, his knocks still went unanswered.

Now the attendant sensed something was wrong. He found the Shopkeeper and said, "I don’t know what’s going on with the guest in Room 9. He hasn’t come out all day and has locked himself inside. Shouldn’t we go check on him?"

The Shopkeeper heard him out and rushed to Room 9, shouting at the door.

There was no sound from within. The door was bolted from the inside and couldn’t be pushed open.

The Shopkeeper propped up a ladder, climbed up, and broke through the paper of the transom window above the door to peer inside.

He saw a person lying on the floor, surrounded by a pool of blood.

The Shopkeeper cried out in fright and nearly fell off the ladder.

Hearing the commotion, the other guests at the inn gathered around, chattering and speculating.

Some said the merchant hadn’t sold a single piece of jade in a fortnight and had killed himself out of despair. Others claimed Room 9 was haunted and a ghost had murdered him in the night. Still others suggested the Shopkeeper and the attendant had killed him for his money...

The more the Shopkeeper listened, the more unnerved he became. ’At this rate, they’ll make me out to be the murderer,’ he thought. He quickly spoke up. "Everyone, a guest has met with misfortune in my establishment. As the proprietor, I certainly bear some responsibility."

"But before the truth is ascertained, let’s not jump to conclusions. The door is bolted from the inside; we still don’t know the situation."

"Since you are all here, I ask you to bear witness. I am going to force the door open and see what’s happened."

Hearing the Shopkeeper’s words, the crowd stopped talking and helped him break down the door.

Once inside, they lit lamps for a closer look. The merchant had been stabbed multiple times in the chest and lower abdomen, and blood was splattered everywhere.

With a dead man in his inn, the Shopkeeper immediately reported it to the authorities.

When Sun Zhang and his men arrived, the guests all testified that the room’s door and windows had been shut before they forced their way in.

The crime scene investigation confirmed this: there was a small hole in the paper of the transom window, and the door bolt was broken in the middle, clearly from being forced open.

Inside the room was a square, earthen kang bed. The bedding on it was folded neatly, showing no signs of having been disturbed.

Against the west wall stood a square table. On it lay an open parcel containing tea leaves, a tobacco pouch, and other sundries.

Flipping the parcel over revealed the mark of the Wanli Jade Shop.

Sun Zhang wondered, ’If this was a murder, how did the killer manage to bolt the door from the inside after making their escape? If it was a suicide, who would stab themselves that many times? Besides, there wasn’t a weapon to be found anywhere in the room.’

There was also the matter of the merchant’s missing jades.

He asked around, but no one had seen anyone enter or leave Room 9.

Room 10 was unoccupied and locked, so Sun Zhang summoned the guest from Room 8 and asked if he had heard any unusual disturbances the previous night.

The guest from Room 8 said he hadn’t heard a thing.

This completely stumped Sun Zhang. A constable suggested, "Could there be a secret passage in the room? Maybe the killer escaped through it."

Sun Zhang thought it was a valid point and ordered the room to be torn apart. They dismantled the earthen kang bed and pulled up all the floorboards.

In the end, they didn’t find so much as a mouse hole.

Then someone else offered a suggestion: "Since the killer stole the jades, they’ll have to find a place to fence them. We can secretly watch the shops in the city that sell jade."

"If anyone tries to sell jade from the Wanli Jade Shop, we grab them first and ask questions later."

Sun Zhang knew this was like looking for a needle in a haystack. The Wanli Jade Shop was well-known throughout Ying Province, so trying to trace the killer through the jades would be incredibly difficult.

Besides, the killer wasn’t an idiot. They wouldn’t try to offload the stolen goods so soon after the crime.

But he had no other options. He could only order the city gate guards to tighten their searches and secretly dispatch men to keep watch. More than half a year passed with no results.

’It can’t be such a coincidence, can it? Could the two cases have been committed by the same person?’

Zhao Lin reviewed the case files in his mind. It felt incredibly strange. The serial rape-murders were crimes of lust, while the locked-room murder was a crime of greed. There was no apparent connection.

...

Since both cases pointed to the Yunlai Inn, Zhao Lin decided to investigate the location in person.

After the morning roll call, he changed into plain clothes, altered his appearance slightly, and walked into the Yunlai Inn.

"Sir, are you looking for a room or just a meal?"

The Shopkeeper looked to be in his fifties. He had a kind face and mostly bald, graying hair. His voice was deep and smooth, reminding Zhao Lin of a broadcaster from his previous life.

The Shopkeeper didn’t recognize Zhao Lin, who had only recently taken over the district. Assuming he was an ordinary traveler, the Shopkeeper greeted him with a smile.

"A room."

Zhao Lin answered succinctly, his eyes scanning the main hall.

The Yunlai Inn didn’t just offer lodging; it also operated as a restaurant. The main hall was filled with people drinking tea and chatting.

"Will you be needing a first-class, second-class, or third-class room, sir? And how many days do you plan to stay?" the Shopkeeper asked.

"A second-class room will do. Perhaps three to five days, or maybe seven or eight. It’s hard to say for now."

Zhao Lin had stayed in inns before while selling bear gall and porcupine quills, so he was familiar with how they operated.

First-class rooms were the best in the inn, usually located on the second floor, with excellent lighting, ventilation, and quiet.

Third-class rooms were cheap, but the conditions were terrible, with one room housing seven or eight, sometimes even more than a dozen people.

Second-class rooms fell somewhere in between, offering both single and double occupancy.

Room 9, where the merchant had died, was on the ground floor and was considered a second-class room.

The Shopkeeper glanced back at the key board on the wall and recited, "We have ten second-class rooms. One through six are occupied, but seven, eight, and ten are vacant. Please, take your pick, sir."

Zhao Lin asked deliberately, "Is Room 9 not available?"

The Shopkeeper glanced around the main hall and lowered his voice. "To be frank with you, sir, there was a murder in Room 9 earlier this year. A guest died in his room, and the case remains unsolved."

"Is that so? You saw it yourself?"

"Of course. It wasn’t just me; plenty of people saw it."

Zhao Lin grunted an "Oh," and said, "Thank you for your honesty."

The Shopkeeper smiled. "We’re in the hospitality business; reputation is everything. If I deliberately hid it, you’d find out sooner or later, and then you’d just come looking for me to cause trouble, wouldn’t you?"

"Why don’t you take Room 7, sir? Rooms 8 and 10 are adjacent to Room 9, so they’re not very auspicious."

Zhao Lin considered for a moment, then said, "I prefer peace and quiet. Which room is the most secluded?"

"Room 10."

"I’ll take Room 10, then."

’Since I’m investigating the case, the closer I am to the crime scene, the better.’

’The guest in Room 8 heard nothing that night. I’ll stay in Room 10 and see if I can find anything.’

The Shopkeeper saw that his advice was not taken, but it didn’t bother him. He had fulfilled his duty to warn the customer. "As you wish, sir. Room 10 it is," he agreed.