Shiller arrived at the door of the classroom where the incident happened.
It was a long corridor, but there weren't many rooms because the entire right side of the hall was the distribution room of this floor. The distribution room was quite large, which meant there were only three doors on the left side: the front and back doors of the distribution room and one door to a storeroom.
There were two classrooms on the right: a larger one and a smaller one, occupying two-thirds and one-third of the area, respectively.
At both ends of the corridor, there was a staircase on one side and an elevator on the other.
Compared to modern architecture, this design was strange, but after all, this was Mercury Base, and it was a Stark-designed Mercury Base at that. Being jam-packed with technology meant exactly that—aside from the sophisticated tech, there wasn't much else, which probably explained the peculiar structure.
Mainly, this wasn't entirely built for living beings; the main workforce of Marvel still consisted of robots on Mercury, and most rooms were only logical for robots. Naturally, robot logic demanded the more direct the better, resulting in this odd layout.
The death occurred in the smaller classroom.
By the time Shiller arrived, several professors had already gathered with another group of students in the larger classroom.
Originally, this wasn't designated as a classroom. Instead, it was a laboratory. The so-called larger classroom was the main laboratory, while the smaller classroom served as the observation room, hence why there was a glass panel separating them.
Now standing in the larger classroom, one could see into the smaller one. Shiller made his way through the crowd to the glass and saw a humanoid creature with light blue skin lying dead against the wall opposite the glass.
The cause of death was obvious; she had a distinct penetrating wound to her chest, right through the heart, and a large amount of blood had poured out from the wound, with the body collapsing into the pooling blood.
She was an Atlantean.
Arthur was explaining the different types of Atlanteans to the other students. Shiller heard enough to categorize them into three groups.
The Ancient Atlanteans were wholly extinct, but there were some close to the ancient lineage who had survived, usually produced through inbreeding. They looked mostly like humans and most were capable of wielding Ancient Divine Power, though their numbers were scarce, likely just a few hundred in all of Atlantis.
The second type were Atlanteans of mixed human descent, like Arthur. Given how long humans had occupied the mainland, interaction with the Sea Clan was inevitable. Despite the opposition to intermarriage with humans, stopping such mixed-race individuals like Arthur completely was near impossible. They could live both in the sea and on land, though their population was relatively smaller.
The most prevalent among the Atlanteans were mixes with the Sea Clan and Ancient Atlanteans, especially after Atlantis sank. The most proximal to the sunken Atlantis were the various Sea Clan territories, naturally leading to these territories receiving the foremost benefit. The majority of Atlantis's residents were of such mixed descent.
Given that several indigenous Sea Clan members were rather oddly shaped, the primary residents of Atlantis varied significantly in appearance. Some had human torsos with fish tails or snake tails, some with scales, gills, shells on their backs, skin hues of blue, green, yellow, black, and purple... a diversity indeed.
The Atlantean who had died was a hybrid of the Sea Clan, with pale blue skin and ears shaped like fins, but no fish tail—she had human-like legs. According to the Sea Clan's gender classification, she was a female.
According to Arthur, her name was Bono, and she happened to be the daughter of a Sea Clan General from his fiancée Mera's territory. She had always been an exceptional student, notably adept in water control. She had stood out in the grand Atlantean selection and came to Mercury Base to study.
Subsequently, Bruce provided more details.
The Sea Clan's physiology differed from humans; one couldn't determine the time of the victim's death by the rigor mortis as the body would not stiffen up, even if left as it was.
However, according to Arthur, Atlantean blood takes about twice as long to coagulate compared to humans, which meant, under normal room temperature, the coagulation time was roughly 20 to 30 minutes.
When Bruce and his team arrived, the blood had not completely coagulated but was close to it, indicating the victim had been killed within the last 20 to 30 minutes.
The camera in the room was broken.
It wasn't a case of external damage or a part failure, but rather, after checking, Bruce found that an internal circuitry short-circuit had happened about an hour ago.
This meant the surveillance in the room hadn't captured what had transpired within that hour.
Cameras outside the room and in the passage stairwell could only capture the situation near the door of the larger classroom but not what happened at the entrance of the smaller classroom, the crime scene.
The elevator camera could capture what happened at both the elevator and the entrance to the smaller classroom, but once the elevator door closed, the camera no longer captured the smaller classroom door.
The natural opening time of the elevator upon arriving at a floor was 20 seconds. This meant that within those 20 seconds when the elevator doors opened, it could capture what happened outside the smaller classroom, but not once closed.
All the people in Shiller's classroom had solid alibis, which unfortunately left the other half of the group that had been attending Victor's class on physical activity today.
The content of the activity class involved exploring pressure and deformation. Victor had required every student to find the most durable object they could within the first 20 minutes of class starting, and the range was not limited to the classroom.
Essentially, the students scattered like a herd of pigs released from the pen. They could go to their dorms, search in the labs, or even ask a professor—once the door was opened, they disappeared without a trace.
This floor was naturally within the range of the students' search, but due to its distance from Victor's classroom, most students didn't come here to look.
And since there was a majority, there had to be a minority; according to other surveillance cameras, a few had indeed come this way, including the victim, Bono.
The remaining few included a student from Gotham Magic Academy named Claudius, the young superhero Blue Beetle Ted, a Mexican lad named Gonzalez, Atlantean sisters Lalali, and Zan, Jenna's brother.
Now, these people had been taken aside individually.
The surveillance on the elevator showed that Bono had left the elevator and entered the small classroom; she was the first to arrive at this floor. However, the other people weren't far behind and arrived within minutes after her.
Hearing this, Shiller gained some basic understanding.
First off, there are indeed surveillance blind spots in this long corridor—when the elevator doors are closed, there's nothing that can capture the entrance to the small classroom.
Moreover, the camera in the small classroom was broken, which meant there was no surveillance from the door to inside the room.
But theoretically, there shouldn't be any blind spots.
Because if you came by the stairwell, you'd inevitably be caught on the camera there, and if you arrived by elevator, you'd be captured by the elevator's camera.
In other words, both ways of moving between floors would actually capture people—there was no way to sneak into the corridor unnoticed.
Of course, before, a magician might have used Teleportation Magic, but because some Magic Academy students unfamiliar with the base layout, affected by other energies in the base, had gotten themselves trapped in walls, the use of Teleportation was strictly prohibited inside the whole base.
Verbal prohibitions might not seem effective, but after all, aside from the small classroom where the camera was broken, the cameras elsewhere weren't malfunctioning; if you teleported, you'd need a starting point, and the camera at the starting point would capture your departure.
The entire base had an AI Butler, which would sound an alarm if it caught you teleporting, but no alarms had been heard within an hour.
However, with the elevator doors closed, the entrance to the small classroom indeed became a dead angle. That meant there could be other blind spots in the base, and this required all students to provide an alibi for not being in a blind spot.
According to the Butler's reports, all students were within the surveillance area during the time of the incident, none entering any blind spots, and none were recorded teleporting.
That's why surveillance is so useful: it basically cleared most of the students of suspicion.
So, with functional surveillance in both the corridor and the large classroom, those who came to this floor should have alibis.
But unfortunately, the camera in the small classroom was broken, and those few had all entered the small classroom.
It wasn't for any particular reason, other than that the classrooms on this floor were unused and filled with various items—something most students knew—and they thought it likely they would find something satisfactory to them, so they took turns searching there.
Bono was the first to arrive, and therefore, she first went into the small classroom to search. Then, she moved to the large classroom, possibly because she didn't find what she wanted there and returned to the small one.
Among the suspects, Blue Beetle Ted and the Atlantean sisters, along with Jenna's brother Zan, went to the large classroom after leaving the elevator. After searching, they didn't go to the small classroom but left via the stairwell at the other end.
Claude and Gonzalez followed the same route as Bono by first entering the small classroom then the large classroom. However, neither of them returned to the small classroom with Bono but took the elevator after exiting the large one.
In short, no one's movements completely overlapped with Bono's, and they each explained their reasonings for searching and what items they found. After inspection, no issues were found.
The timeline of everyone's testimony was consistent, corroborated by mutually seeing each other or by leaving, which also matched with the surveillance footage of the large classroom and corridor.
This meant that we're looking at a classic scene of a locked room murder.
Some might say, but didn't Gonzalez and Claude also enter the small classroom? How does that qualify as a locked room murder?
The issue is, they left before Bono, and the elevator surveillance camera captured them boarding the elevator, with all subsequent movements traceable, negating any possibility of them returning.
Meaning, after they left, the small classroom became a sealed chamber.
Some might still ask, after they took the elevator and the doors closed, wouldn't the surveillance inside the elevator not capture the entrance to the small classroom? It's unknown if anyone else went in.
But at that moment, the elevator was occupied; anyone wishing to enter the corridor would have had to use the stairs—where a camera was also present, and any entrance to the corridor would be captured.
So, the locked room isn't just the small classroom but the entire corridor along with this one room.
Of course, it's also possible someone used Invisibility Magic, but let's not forget, other than the Mexican young man being human, the rest all had their own talents, varying at least slightly.
Claude himself was a magician, and just as with the principles of a Stand Messenger, if someone used magic at such a close range, he would feel it.
And he happened to be the last person to see Bono, which means if someone had used magic before that, he would have sensed it.
Beside, like with Teleportation Magic, you'd need a place to start casting Invisibility Magic, which could result in a discontinuity in the surveillance footage where you abruptly vanished, promptly discovered by the AI Butler.
However, the rest of the students didn't have such issues. The footage of them captured by the cameras was continuous, without even a second outside the range of surveillance.
This is getting interesting, Shiller thought. These cases are much more complex than he had imagined.
And what made this different from previous cases was not the state of the body but the fact that it had been a long time since he'd encountered such a traditional murder case with such a well-defined timeline process.