Before Kogoro could speak, he was answered by Hattori Heiji first. "Judging from the purple lips of the deceased, it is basically certain that it was poisoned."

"Then under the deceased's right ear, there is a small dark red dot left by being stabbed by something, plus the metal needle not far from the corpse, judging from the blood spillage, the diameter of the wound at the time is very consistent."

"As long as you confirm whether the metal needle is the same poison as the poison in the deceased, you can determine whether it is a murder weapon. I think the killer first stunned the deceased and then killed him within half an hour before we came. ”

Although Officer Twilight understood everything, he was puzzled by Hattori's identity, and he tilted his head and whispered about Kogoro. "I mean, Maori brother, who the hell is this man!?"

"He's called Heiji Hattori, and he's a high school detective from Osaka." When Officer Twilight heard Hattori's identity information, he was stunned for a moment, and then he remembered.

"It turns out that you are the son of the chief of the Osaka Police Station, the famous high school detective Hattori Heiji!" "Yes, that's me! But can you not mention my dad! It wasn't because of him that I became a detective in Kansai! ”

Heiji Hattori was in a very bad mood, and although the people in Tokyo also knew his name, which made him happy, but if it was because of his father, it would be different.

Regardless of his mood and thoughts, Officer Twilight came up to Kogoro. "Brother Maori, you have to work hard this time! Don't let people from Osaka come to us and steal the limelight! ”

"Well, just leave it to me with confidence!" After remembering the plot, Kogoro was naturally full of confidence. "All the windows in the study are locked from the inside, and the only entrance and exit is the door."

"So Mrs. Tatsumura, do you have a lot of keys in this room?" Officer Twilight told his speculation, which was also a necessary process for the investigation of the case.

"No, there are only two keys in this study. One is with me, and the other should always be with my husband. "On him!" When several people heard her words, they were shocked.

Tatsumura had come back with Kogoro and the others, and they had seen her take out the key to open the door, so it was not a matter of course that she had committed a crime, and she was still at the Maori Detective Agency half an hour ago.

And if it's the key to the other house, it's still on Tatsumura's body. Then the room becomes a secret room, and the murder case in the closed room is notoriously difficult to solve.

At the thought of this, Officer Twilight couldn't help but frown. Then he walked briskly to Tamura's corpse, and quickly retrieved the key from his right pants pocket.

"It's really still there, it looks like this has become a real secret room!" His face looked very serious, and he obviously had a hint of doubt about Kogoro's ability to solve the case.

The key was quickly taken by forensic personnel for further testing. Before they took it, Kogoro and the three detectives took a closer look at the style of the key, trying to find clues that the killer had disguised this place as a secret room to kill people.

During this period, Hattori Hei looked at Kogoro and Conan many times. For two people, one big and one small, but they are both doing investigations, he feels very strange, but he can't say the specific reason for that feeling.

Shaking his head, he quickly dispelled those thoughts from his mind and focused his attention on the case. At this time, the inquiry about the Dacun family was also completed.

Based on their respective testimonies and clues, the police quickly ruled out the suspicion of Dacun Gongjiang and the housekeeper who had 'sufficient' alibi, and focused their investigation on the other three.

Just as they were exchanging opinions, a police officer hurriedly ran in. "Officer Twilight! We found this inside that keychain just now! With that, the officer handed a keychain to Officer Twilight.

The keychain was oval-shaped, now split in half, with only a bearing connection at the tail, and a small piece of tape abruptly attached to it.

There is a small gap at the midpoint where the tape meets a keychain. Judging from the clues that everyone has so far, it should be the place where the poison needle is hidden.

But it's really strange why the murderer hid it in the keychain that the deceased was carrying. How the hell did she get to this? And why do you want to do this?

Kogoro knew all this, and the other party just intended to show that this was a secret room to make an alibi for himself.

At this moment, Hattori Heiji seemed to have figured out something, and after talking a few words to the housekeeper, he hurriedly ran out. Kogoro knew what he was going to do, but it wasn't necessary anymore.

"Officer Twilight, I've figured out all the facts of this case!" "What!? Brother Maori, you already know who the murderer is!? Officer Twilight looked at Kogoro in amazement, not expecting to solve the case so quickly.

Kogoro put his eyes directly on Tamura Gongjiang's body, with a slight smile on his face. "In fact, this case is very simple, the murderer just used some small means to kill the deceased openly!"

"What!? How can it be!? "Everyone was almost shocked that something like this could happen. Officer Twilight was very dissatisfied, and directly opened his mouth to urge.

"Brother Maori, don't sell it, just say it quickly!" "No problem, I'll make this case clear!"

The murderer first used drugs to stun the deceased, and then posed for him to sleep on the table. Then, while we were with her, we secretly killed him with a poisoned needle, so that she would have a perfect alibi. ”

Although Kogoro has not named his name yet, the people in the house have a detailed understanding of the course of this case, and they know that he is talking about Dacun Gongjiang when they hear it.

In the face of everyone's surprise, incomprehension and doubt, her face remained unchanged, and she calmly began to refute Kogoro's reasoning. "Mr. Maori wants to say that I am the murderer of my husband!"

"But I want to ask you, why did you say that the murderer was mine, and how did you kill him in front of you?"

Kogoro didn't care at all about her calmness and rebuttal. "You are said to be a murderer because only you and the deceased have one key in each hand, and neither of them is missing."

"To achieve such a secret room, only you can do it! As for the course of the murder, we have to talk about the situation in the house at that time. ”