The fairy maid cheers for her deceased master today.

Axe continued to observe from the center of the hotel room, his gaze sweeping over the outlines drawn in white chalk on the floor—each line corresponding to a part of Caroline's body.

James's idea makes some sense. The aliens attacking the fairies doesn't need to be controlled; it's their instinct.

But the alien species needs to leave quietly... at least without making too much noise... it definitely can't leave through the door. It must have left through the window.

Ax looked out the window and saw that Elena had walked to the window, her fingertips lightly touching the window frame, and she slowly closed her eyes, as if trying to catch the faint movement in the air.

"Elena, can you feel anything?" Ex couldn't help but ask.

Irena took a deep breath and slowly opened her emerald eyes: "The magical fluctuations have almost dissipated, but... there are still some residual traces. Fortunately, I am quite sensitive to fluctuations."

As she spoke, she walked to the center of the room, gently raised her hands, and a pale green light slowly emerged from her palms.

"Look here," Elena pointed to a spot on the floor, "there are traces of a barrier here, though extremely faint, it is definitely there."

Officer James immediately leaned closer, staring curiously at the seemingly ordinary floorboard: "Really? I can't see anything there?"

“Ordinary humans can’t see them,” Elena explained, “but to me, these marks are as clear as if they were just drawn on.”

Ex walked over to her, squatted down, and examined her closely.

After observing for a while, X finally realized that he was also an ordinary human, so he simply asked:

"What did you see? Why don't you describe it?"

"There used to be a circular barrier here, about two meters in diameter," Elena said, tracing a circle in the air with her finger. "The residual energy from the barrier spiraled outwards from the center. And..."

She suddenly stopped, her brows furrowing slightly: "Strange, there are traces of a second layer of barrier here."

"The second floor?" Ex raised an eyebrow.

"Yes, the first layer of the barrier is located inside the room, while the second layer..." Elena pointed to the window, "The second layer of the barrier almost covers the entire room, and at the same time, it creates a passage that extends from the center of the room all the way to the outside of the window."

James jumped up excitedly, "I knew it! Lucy must have used a barrier to trap the aliens first. When Caroline returned, the first layer of the barrier was triggered and broke, allowing the aliens to attack her and then escape along the pre-set route of the second layer of the barrier!"

This was also what Ax had just envisioned.

By using a barrier, the movement range of the alien species can be controlled. This can indirectly control the alien species.

But soon, Ax also realized the anomaly.

"Wait a minute," Ex pressed, "The second layer of the barrier covers the entire room, so shouldn't Caroline have noticed when she came back? Shouldn't she have sensed it when she passed through the barrier?"

Caroline is also a professional in charge of barriers. She shouldn't have been unaware of such a powerful barrier magic.

"This... might be an advanced technique for using barriers."

Elena said uncertainly.

"When the first layer of the barrier breaks, the second layer of the barrier is automatically triggered, which is just enough to trap the alien and Caroline together."

Angel exclaimed in surprise. She hadn't expected it to be used in this way.

Indeed, such advanced use of barriers is something that a novice like Angel cannot master.

"There's another problem," X shook his head, "If the mutant escaped through the window, shouldn't the people in the hotel, or those around here, have seen it?"

"The Thames is right behind the hotel," Officer James pointed out the window. "The aliens could easily jump out the window and disappear into the river without a trace."

Elena nodded: "That hypothesis makes sense. Let me simulate the barrier's form at that time."

She closed her eyes, her hands moving slowly in the air. The green light in her palms gradually condensed, forming a complex three-dimensional structure. Within the light, two concentric circles were clearly visible: the inner circle radiated binding energy, while the outer circle extended a passage leading directly to the window.

But it only lasted a few seconds before the large barrier dissipated. Elena shook her head. She could only simulate a rough outline, but couldn't maintain it.

"Look, this is roughly the structure of the barrier at the time," Elena explained. "The inner circle was responsible for trapping the aliens, while the outer circle was the escape route. When Caroline entered the room, the inner circle barrier was triggered, and the aliens were released to attack her. They then fled towards the window following the direction indicated by the outer circle barrier and finally jumped into the river."

James then added, "Lucy and Caroline are both fairies responsible for checking barriers, and they are both proficient in barrier magic. Therefore, only Lucy can do this."

Axe couldn't help but recall what Deacon Samuel had said in his letter.

……

Caroline is the dedicated fairy responsible for inspecting the cargo barrier at the docks. She has the authority to enter and exit the area and the ability to alter the barrier's state. She is highly suspicious.

Lucy was also a suspect. She and Caroline were in the same group. Because inspecting the goods required two people to work together and supervise each other, she was also considered a suspect.

……

The barrier marks before us indeed confirm the deacon's testimony.

X recalled the magical structure. Both its structure and triggering method were clearly extremely professional.

Lucy is indeed more suspicious now.

Angel nodded at this point, also agreeing that Lucy had done it.

"I knew it!" James exclaimed, pleased with the agreement. "Lucy definitely did it!"

"Don't jump to conclusions," X stood up. "We need more evidence. Let's go outside the hotel and take a look. If the alien really escaped through the window, it should leave traces."

The group left the hotel and went around to the back of the building.

The hotel's back wall bordered the Thames, whose waters flowed quietly, reflecting the hazy sky. Elena carefully examined every detail of the wall.

Finally, she noticed something amiss in the corner.

"Found it!" she suddenly exclaimed, pointing to several marks on the wall. "These are the moving traces left by the Swamp Xenomorphs. Look, only Swamp Xenomorphs have these slime-like marks."

X leaned closer to examine it and indeed saw several dark, slimy marks on the wall, extending from below the first-floor window all the way into the river.

"This definitely confirms our hypothesis about the barrier trap." James excitedly pumped his fist. "Great! I knew the culprit was Lucy! Case solved!"

I felt this police officer was being overly excited. Are all rookie police officers this energetic?

“But,” Elena suddenly hesitated, “to cast such a large-scale barrier, it should be quite conspicuous that night, especially the barrier around the windows and the area outside the windows. The barrier will emit a faint glow, and with so many people staying in the hotel, it’s impossible that no one will notice it.”

Ax stroked his chin, lost in thought.

"Based on the police's time of death, Caroline was likely murdered at night, when there were probably still many people in the hotel."

Moreover, it's an old hotel with people coming and going, often with people around even at night. Someone is bound to notice something unusual outside the hotel.

"Could it be that Lucy used an invisibility barrier?" James guessed, still wanting to pinpoint the suspect.

"An invisible barrier?" Elena shook her head. "That kind of barrier requires extremely high magical control and lasts for a very short time. It's almost impossible to trap an alien species for that long."

"Almost impossible, which means it's still possible," James chuckled.

"But we're not that professional when it comes to barriers. Officer James, if you really think it's possible, you should still have the fairies from the Royal Magic Society take a look," X suggested.

James readily agreed.

Just then, Angel's gaze swept across the back wall of the inn, and she suddenly noticed something: "Master! Look, look! What's that?"

She pointed to a small hole above the first-floor window, which looked like it had been drilled by something: "What's this hole?"

Elena stepped on the vines, lifted them up, and got closer to observe.

She lightly touched the small hole with her fingertip and found a metal box about the size of a fingernail inside: "This is... a magic detector. The Holy Path Society often installs these devices in important locations to monitor abnormal magical fluctuations."

"The Church of Christ?" James asked疑惑地, "What does this have to do with the case? Why would the Church of Christ be paying attention to this hotel?"

"It might not have been installed by the Holy Path Society. Elena, these kinds of detectors should be sold in many places, right?" Ax asked immediately.

"Yes, Sir Ex. The Royal Magical Society collaborates with some mechanical workshops and can sell these harmless metal boxes," Elena said.

"Then let's check the serial number or style. Let's see if we can find a seller."

Since it's right below the barrier...

This detector might be used to monitor and test the barrier.