Although Sherlock didn't mention Barty's issue, he did tell Kingsley about the Hand of Glory.
"I connected the Hand of Glory to one of the fleeing Wizards, but the connection broke after showing the location for just a moment. Someone among them must have noticed the problem. The final location was a small town in the northernmost part of Derbyshire. You can send someone to investigate now, but it's highly likely they won't find anything."
Kingsley naturally took Sherlock's words very seriously. He immediately went out and instructed two Aurors who could Apparate directly to Derbyshire to investigate the situation before returning to the Interrogation Room.
"Where did you get that Hand of Glory?" he asked, frowning.
Sherlock didn't tell the truth. He shrugged and made up an excuse.
"I bought it in Knockturn Alley from an unknown Wizard. You have to keep this a secret for me; I don't want to be charged with illegally purchasing Dark Arts items."
Kingsley nodded.
"Even if it's discovered, it's fine. You used a Dark Arts item to help the Ministry of Magic with official business; no one will hold you accountable."
"A civil servant speaks differently, after all."
Afterwards, Kingsley simply took a few statements from them and, after applying to his superiors, released Sherlock and Hilke from the Ministry of Magic.
After leaving the Ministry of Magic, Sherlock's face, which had been relatively relaxed, slowly grew grim.
Hilke noticed the change.
"Did something go wrong?"
Sherlock frowned deeply.
"The reason the Hand of Glory is classified as a Dark Arts item isn't just because its material requires a human hand; the tracking magic attached to it is almost impossible to detect. But now the connection is broken, which means someone instantly spotted the problem with Barty."
"To have such keen eyesight means he has recovered some of his power," he muttered to himself.
Then he turned to look at Hilke.
"Help me report that I'm safe to the Weasley family. Just say I'm fine. I need to go to Hogwarts now."
Hilke nodded and left using Apparition.
After she left, Sherlock didn't linger long either. He went straight to Hogsmeade and returned to Hogwarts Castle.
There was still a week until school started, and the Castle was very quiet. He followed the stairs all the way up and went directly to the gargoyle on the third floor.
"Is Professor Dumbledore in his office right now?"
The gargoyle didn't speak, but remained silent for a moment, as if consulting the person inside the office.
A few seconds later, it jumped aside on its own, revealing a path forward for Sherlock.
Sherlock followed the spiral staircase to the end, reached the eighth floor, and pushed open the door to Dumbledore's office.
Dumbledore was holding a letter, looking seriously at its contents. Only after Sherlock entered did his expression soften.
"Hoh, I just received news that an accident occurred at the Quidditch World Cup. I was wondering if you might come to see me today, and here you are."
Sherlock, however, did not appear as relaxed as Dumbledore. He controlled his expression, making his current thoughts unreadable, and sat down opposite Dumbledore.
"I saw Barty Crouch Jr. in the stands."
Sherlock's words made Dumbledore's face turn solemn as well. He put down the letter in his hand and signalled Sherlock to continue.
"You should know that I mastered a unique kind of magic from the things my mother left behind. I used this magic to discover Barty Crouch Jr., wearing an Invisibility Cloak, in the stands during the final match. He was accompanied by the Crouch family's House-elf, Winky."
Since they were both intelligent people, no further explanation was needed. By simply emphasising this matter, Dumbledore could grasp the underlying issue.
"Crouch knew his son was alive and had been hiding him all this time," Dumbledore said gravely.
"Moreover, Barty's condition was very strange. He seemed to be controlled by Old Barty, and that House-elf was constantly watching him."
"When I went back in time, there was a grudge between him and me, and I felt that his attendance at the World Cup final was not simple, so I tracked him after the match ended."
"The timing of the chaos was very clever. Someone was helping Barty create an opportunity to escape. He succeeded in the end, casting a Dark Mark into the sky and meeting up with three masked individuals."
Dumbledore spoke softly.
"Death Eaters."
"Yes, Death Eaters. They all had the Dark Mark tattoos, and combined with those masks, they were the Death Eaters who disappeared after the Dark Lord vanished and were never purged by the Ministry of Magic."
"They tried to take Barty away, but I stopped them. Then Barty recognised me and spoke my mother's name."
As Sherlock spoke, he kept his eyes fixed on Dumbledore's. He paused deliberately at this point.
"He told me some secrets that you have always been unwilling to tell me."
Dumbledore's gaze was profound. He seemed to be deliberately avoiding Sherlock's eyes, lightly tapping the surface of his desk with his fingers.
"He wanted to provoke you."
"I don't deny that," Sherlock said calmly. "And he succeeded. I was truly furious, so angry that I even intended to use the Killing Curse, and I acted on it."
Dumbledore immediately frowned tightly.
"Did you kill them with the Killing Curse?"
Sherlock took a deep breath.
"Perhaps because it was my first time using the Killing Curse, the curse I cast didn't have the effect of immediate death. They just bled continuously without dying. When they tried to escape, I killed two of them using Transfiguration."
Hearing this, Dumbledore's frown eased. His gaze towards Sherlock was complex, but the strongest emotion was relief.
"Dark Arts, especially the three Unforgivable Curses, require the caster to possess boundless malice to succeed. Compared to the other two curses, the Killing Curse demands this even more. I am very glad, Sherlock, that even though you were provoked and deeply angry, you still didn't manage to cast that curse successfully."
"What would happen if I had succeeded?" Sherlock asked blandly.
"Nothing immediate, but Dark Arts are very dangerous, and their corruption of a person's mind is not achieved instantaneously," Dumbledore said, his voice calm yet incredibly serious. "Many Wizards, after successfully casting the Killing Curse for the first time, become immersed in the pleasure of arbitrarily taking another's life and begin using the Killing Curse recklessly. It is at this point that the Dark Arts corrupt their minds."
Sherlock understood what Dumbledore meant, but he thought of more.
When he used the Patronus Charm with hundreds of wands simultaneously, the excessive positive emotion completely infected him and affected his thinking.
If he had truly succeeded in casting those hundreds of Killing Curses tonight, what would the resulting negative emotional feedback have turned him into?
He didn't dwell on it, but he became vigilant, resolving to avoid using multiple wands to cast Unforgivable Curses like the Killing Curse in the future.
"I want to know if what he said was true," Sherlock asked calmly, stating the reason for his visit while staring into Dumbledore's eyes.
"Being captured by Lord Voldemort, tortured into madness, and then released."
Dumbledore fell silent.
He maintained eye contact with Sherlock quietly for a long time without speaking.
After three minutes, he finally sighed, stood up from his chair, and paced around the office, clearly hesitating.
"Did you kill Barty later?" he asked an unrelated question.
"Yes, but I let one person leave," Sherlock concealed nothing. "That Death Eater took Barty's body away. I wanted to use his body to find the Dark Lord's current hiding place, but the magic I placed on Barty was discovered just as I got a location."
Dumbledore did not seem overly surprised by this result.
If Lord Voldemort were so easily outwitted, he wouldn't have such a massive influence in the Wizarding World.
"Did the Death Eater who escaped recognise you?"
"He called out my identity."
Sherlock's words seemed to solidify Dumbledore's resolve. He turned and walked towards the wall covered with portraits of previous Headmasters, finding the portrait of an elderly, kind Witch.
"Dilys, give me the contract."
The kind Witch in the portrait seemed to take something out of her robe pocket, then handed it to Dumbledore through the Portrait Frame.
That old piece of parchment magically passed right through the Portrait Frame, and Dumbledore reached out and took it.
Sherlock had been watching Dumbledore's movements. He saw more than a dozen densely packed names on it; some had turned grey-white, while others were still the colour of dark green ink.
After Dumbledore received the contract, he had no intention of showing it to Sherlock. Instead, he waved his hand, summoning Fawkes the Phoenix, who was perched on a golden perch behind the door, and handed the parchment to its sharp beak.
"I apologise for the trouble, Fawkes," Dumbledore said softly.
Fawkes let out a cry, as if giving a response. It held the parchment in its beak and returned to the golden perch, flapping its wings twice. Then, a golden-red blaze suddenly erupted around its body!
A painful bird cry sounded.
The flames instantly consumed Fawkes's entire body, as well as the parchment!
"That contract can only be destroyed by the flames produced when a Phoenix undergoes rebirth. Although it wasn't Fawkes's time yet, we had no choice but to ask it to advance its rebirth."
Dumbledore looked at Fawkes, who had become a fireball, and gently explained to Sherlock.