The head was hidden at the crime scene, in Olga Marie's room. However, it wasn't in the real world but concealed within a subspace. The one who hid the head was the victim herself, Trisha.
Trisha had Mystic Eyes, similar to Shizune Seo's, which allowed her to foresee fragments of possible futures. These predictions were not definite and could occur at any time. When Trisha foresaw that she would be beheaded, it was already too late. She only had time to hide her head in a subspace at the moment it was cut off—her attribute, like Sakura's, was Imaginary Numbers, making this kind of magecraft her specialty.
In subspace, time is frozen, so the head remains unchanged from the moment it entered until it was retrieved, allowing Trisha to leave a final message. After all, there is a slight time delay between decapitation and brain death.
The moment the head left the subspace, Trisha's remaining consciousness revealed the name of the killer—Karapa.
Karabo Frampton, a Black man over 70 years old, was affiliated with the Holy Church. He was the only guest who did not attend the auction because he had already been detained for murder.
Even if he hadn't been detained, he might not have attended, as he was there to sell, not buy Mystic Eyes. The Mystic of Transcience that Shinji bid on was provided by him.
Using the mysterious power of the Mystic of Transcience, Karabo managed to kill Trisha before she could react.
The Mystic of Transcience can recreate past events in the present. By pre-setting a slash, when Trisha reached a designated spot, the slash would be re-enacted.
Karabo insisted he did not know about his eye's ability or have any memory of such incidents. However, in Adashino's scheme, the auction house's agent revealed the eye's ability just in time.
Karabo had previously used retrospective vision to look at Trisha's corpse and claimed not to have seen the killer. This statement was significant proof—he wasn't lying because the killer never entered the room. Since the train was constantly moving, there was no need to enter Trisha's room. A simple slash in front of the moving train would decapitate her minutes or seconds later.
Additionally, there was another piece of supporting evidence. Seven years ago, a series of murders occurred in which the victims, like Trisha, lost their heads. The Holy Church had sent an investigator, but no progress was made, and the case was left unsolved—the investigator at the time was Karabo.
With so much direct and indirect evidence, Karabo's defense seemed weak. The truth was out, and the only thing left was to send the criminal to the Clock Tower for trial after the auction.
Only Waver expressed dissent because he couldn't find Karabo's motive—what he always emphasized as the Whydunit. Although he acknowledged Adashino's reasoning, he insisted the case wasn't closed until this was resolved. Based on the clues he had uncovered earlier, he was certain there was a deeper truth behind this incident.
So even after Karabo was captured, Waver continued his investigation. Luckily, after a night of rest and treatment, his body had recovered, and he was ready to investigate in peak condition.
Now it was time for him to reveal the results—Waver Velvet was the Clock Tower's greatest detective. Other people's reasoning and deductions couldn't steal his thunder!
Alright, Waver wasn't like that; this was just Shinji daydreaming out of boredom.
Yes, boredom.
Whether it was in the Castle Adra or Iselma, some people and events caught his attention.
But in this Mystic Eye Train incident, there was nothing—at least, no one he cared about had appeared so far. Not having been there from the start, he couldn't be bothered with the convoluted reasoning that could fill five or six thousand words. Playing a staring contest with Arcueid at the table was more fun.
Fortunately, Waver's reasoning was about to end, and it was time to reveal the real culprit.
"The killer is you. You are the one who manipulated Karabo Frampton and killed Trisha Fellows."
As he uttered the classic line found in all detective novels, a white light flashed through the carriage.
A vortex of light suddenly erupted from Trisha's head, binding the limbs of the real killer like chains and isolating the interior from the outside.
Indeed, Karabo had never lied. He truly did not know about his abilities or the identity of the killer. Although he killed Trisha and committed the crimes seven years ago, he was unaware of it all, as he was being manipulated into committing these acts unconsciously.
The true culprit's motive was simple—Trisha's future sight. She foresaw a high-level Mystic Eye auction on the Mystic Eye Train and her encounter with Karabo. She hoped to uncover the truth from seven years ago through Karabo, even considering the possibility of his being manipulated and preparing for it. This was something the true culprit could not tolerate.
They had to eliminate her before she found out the truth!
Because of the existence of future sight, Trisha could predict most attacks, so the true culprit chose to attack from the blind spot of her vision, striking from the past to kill her.
However, Trisha didn't leave without any backup. Given the dangers of the Mystic Eye Train, she deliberately left a subtle clue pointing to the events of seven years ago in her previous exchanges with Waver, which became the key for Waver to uncover the truth.
"Professor, please stop joking—"
The one bound by the chains of light, Caules, smiled.
At first, his expression seemed as if he thought Waver was joking, but after confirming that neither Waver's statement nor the barrier had budged, he shook his head in confusion.
"A-Are you serious?"
"Of course."
"It seems you've convinced yourself that I am the killer, but here, your mere words won't suffice. You understand that, right?"
"Indeed. If the only ones present were magus, the Department of Policies would suffice. But this Mystic Eye Train belongs to the realm of Dead Apostles. So, besides reasoning, you need evidence to convince the auction organizers. Just as Miss Adashino prepared Trisha's final message and the auction manager's testimony to prove Karabo's Mystic Eye ability."
Waver admitted this calmly, then turned around.
"So, I called someone—a person who came all the way here. Thank you for your hard work."
There, in Waver's former seat beside Gray, stood another person.
"Luckily, I caught a ride, so it wasn't too hard."
The young man shook his curly hair and adjusted his crooked glasses. His height, appearance, and even demeanor were identical to those of the one bound in chains.