"By the way, who are you?"
Hattori Heiji heard my words, took off his hat, and introduced himself.
"My name is Hattori Heiji.
I'm a high school detective like Shinichi.
Nice to meet you."
Hearing that, Kogoro seemed to recall something and said.
"Now that I think about it, I've heard there's an excellent high school detective in the Kansai region."
"Yes, in the west there's Heiji, in the east there's Shinichi — we're always compared.
So I came to check."
Hearing that, Ran asked Heiji.
"Check what?"
"Whether Shinichi is really a guy worthy of being compared to me!"
"You've come to the wrong place.
I haven't seen Shinichi for quite a while either."
"Really? Hmm... Well, I heard he's Ran's fiancée."
Ran blushed at those words and didn't know what to do.
"F-Fiancée..."
Then Conan flared up and asked.
"Who said fiancée!?"
"Sonoko said that, but why are you getting worked up?"
"Ahahaha... She's a close sister, so I was curious..."
Just then, there was a knock at the entrance.
When we turned around, a lady had already come in and was standing there frowning, knocking on the entrance door.
Knock knock knock!
"How many times do I have to ring the doorbell? This office has terrible customer service."
Kogoro looked at the lady and said.
"Wh-What can I do for you?"
For now, Kogoro guided the lady to the guest table and sat her down to talk.
Ran prepared tea and gave it to the lady and Kogoro.
"So, you're talking about a background check on your son's girlfriend?"
"That's right.
These are photos and records of that child."
The lady handed various photos and documents to Kogoro.
"Katsuragi Yukiko, 24 years old.
Graduated top of her class from Mitsuba Middle High School... Currently enrolled at Touto Medical University.
Diligently working to become a doctor..."
Kogoro asked the lady, puzzled.
Because the documents the lady gave didn't seem to have any problems.
She looked like a woman with good credentials and a diligent attitude.
"Um... Do you have any complaints?"
"No.
I don't have complaints.
It's just..."
Interrupting the lady, Heiji said.
"Because she's too perfect, you don't like it, right."
"What?"
"Humans are all suspicious and jealous creatures.
When we see something perfect, we try to find flaws.
Right?"
The lady looked at Heiji and said.
"Who is this child?"
"Ahahaha, well, she's my daughter's friend."
Kogoro gestured to Heiji not to interrupt.
"Anyway, let's talk about the details at my house.
My husband is waiting too..."
"Huh? You're going now? Then you should've both come together from the start..."
"As I said earlier, he's a diplomat, so if it's known he frequents places like this..."
Heiji cut in again and said.
"He'll be the subject of gossip.
That's what you mean, right? Good, I'll go too!"
"What!?"
"It's better to take kids than to go with just the uncle.
It'll raise less suspicion."
Hearing that, the lady seemed to agree.
"I see.
Then please come along."
At Heiji's words, we decided to go along too.
Conan was going too, so I said.
"Conan, it'd be better to rest at home, wouldn't it? You have a cold."
"The shot helped, so I think I'm getting better."
I touched Conan's forehead and checked his temperature.
"Hmm... This won't do.
You want to go that badly?"
"Yeah."
"Can't be helped, then."
I put earmuffs on Conan, put a mask on him, and wrapped him tightly in a thick cloth like a swaddle and carried him on my back and moved.
"Brother, you don't have to do this..."
"Hey~! A cold gets worse with cold wind."
Seeing that, Ran laughed and said.
"You look just like a dad carrying a baby."
Hearing that, I showed Conan to Ran and said.
"This is our baby Conan.
Isn't he cute?"
"Hehehe~ Yes, he's cute."
"Ugh! Put me down right now!"
"No way."
Seeing that, Ran burst out laughing.
"Pffft~"
And so we moved to the diplomat's house.
Being carried around like that, Conan was getting irritated and kept squirming, but with strength beyond human, there was no way the cloth tied with sailor's knots would come loose.
"Ugh... Damn it! This humiliation..."
"Oh my, the child is lively."
"Right? I'm thinking of making him an athlete later."
Hahaha~ Hohoho~
Just then, Kogoro said.
"It looks like we've arrived, so we should be quiet."
"Yes."
We entered the diplomat's house.
It was a pretty big house.
About the same size as mine.
"Please come inside."
"Ah, yes."
Inside, the housekeeper greeted us and welcomed us.
"You're back, madam?"
"Is he in?"
"He's probably still in the study on the second floor.
And who are these people?"
"He's an old friend of mine, Mori-san."
"I see.
Shall I bring something out?"
"Yes, please."
At that moment, the real person from the photo the lady showed, Yukiko, came and greeted the lady.
"Mother! I came to visit."
"Why are you here?"
Behind her, a man who seemed to be this house's son said.
"I called her.
Father won't meet Yukiko, so I had no choice but to call her.
But Father still won't come out of the study."
Yukiko saw us and said.
"Oh my, are these Mother's friends? Oh? Isn't that the onmyoji Jin???"
"Nice to meet you.
I'm Jin."
"Wow~ I can't believe I meet a celebrity... By the way, who's the child you're carrying?"
"Ah~ This child is a younger brother I know, but he caught a cold."
"I see."
At that moment, the lady frowned and said.
"Don't interfere.
And why do you call me mother! You don't even know your place!"
"I'm sorry..."
The lady scolded Yukiko and then guided us again.
"Well, let's go this way."
"Ah, yes, yes."
We were guided by the lady and about to go up to the second floor when an old man was coming down the stairs.
"Oh my, Father, when did you come?"
"What are you talking about, girl? Didn't you call me saying you wanted to hear about the fish I caught?"
The grandfather showed us a 'gyotaku' — a print of the fish he caught on paper — and bragged.
"How is it? It's a pretty big one, right?"
"Ah, yes... it really is.
Then please go to the living room first.
I'll be right there."
"Alright."
Kogoro, seeing the old man go down the stairs, asked the lady, puzzled about making an appointment when it would take time because of the request.
"Is it okay to make such an appointment?"
"It doesn't matter.
He'll forget soon anyway.
Father's forgetfulness has gotten worse lately."
"I-I see."
We arrived in front of the study door on the second floor, and the lady knocked on the door.
Knock knock knock!
"Dear, we have guests! Dear?"
There was no response from inside the study.
"That's strange... Is he not inside?"
The lady took out a key from her handbag and opened the door.
Then inside, the person who seemed to be a diplomat was sitting at the desk with his chin propped, looking like he was asleep, and music was playing in the study.
"Good grief.
Leaving the audio on and sleeping in a place like this... Dear, wake up! Dear!"
The lady tried to shake the diplomat awake, but the diplomat just collapsed to the floor.
Thud!
"Ah!! Dear!! Wake up!"
Me, Kogoro, and Heiji hurriedly went over to the collapsed diplomat and checked his condition.
"This is... he's already dead."
"Ah... It can't be..."
People who were downstairs heard the noise upstairs and hurriedly came up.
"Madam, what is it?" "Father?"
Seeing that, Kogoro said.
"Everyone!! Don't come into this study until the police arrive! Madam, don't move from there either!"
"What's going on?"
"The owner of this house, the diplomat, has passed away."
"What!!!???"
Conan, who I was carrying, tried desperately to see the situation and stuck his face over my shoulder.
So I bent down slightly to show him the situation.
"Goodness, doing detective work again? Here~"
"Ahaha, brother, thank you."
I pretended to look at the body.
I already knew from the original who the culprit was, but I couldn't say it right away, so I had to at least pretend to look at the evidence.
"It's still warm? And the lips and fingertips are starting to turn purple.
Then he hasn't been dead long, and it's poisoning."
"Brother! Over there."
I looked where Conan pointed, and near the diplomat's neck there was a mark like something had been stabbed.
I immediately called Kogoro.
"Detective!"
"What is it? Son-in-law."
"Look here."
I explained what Conan and I found to Kogoro.
"I see.
He really hasn't been dead long.
On top of that, the lips are starting to turn purple and there's even a puncture mark, so this is poisoning.
Then there must be a poisoned needle too."
At that moment, Heiji pointed to the floor where a poisoned needle was and said.
"It's here.
I just found it."
"Right, there might be fingerprints, so don't touch it."
"Understood."
Heiji had been trying to take the lead since Kogoro wasn't doing much reasoning, but since I gave information to Kogoro this time, Heiji wasn't stepping forward or anything.
"Conan, how's the cold?"
"The shot helped, so I think I'm feeling a lot better."
"Good.
Still, when we get home, take medicine and rest well."
"Yeah, thanks."
He didn't drink the baijiu, so Conan's condition didn't look bad.
After waiting a bit, the police arrived.
Of course, Inspector Megure Juzo came this time too.
The forensics team came in and looked around everywhere.
"Hmm... All the windows are locked from the inside.
It would be difficult to come and go from outside.
Then we have no choice but to think that someone among you used a key to come in through the only entrance."
Inspector Megure looked at the lady and asked.
"Madam.
How many spare keys are there for this study?"
"There are only 2 keys.
One is this key I have, and the other is with my husband."
"With your husband?"
"Yes, he always keeps it in his pants pocket."
Inspector Megure rummaged through the dead diplomat's pants.
Then, from the pants pocket, inside the coin pocket, a key was found folded up.
"This can't be..."
At that moment, I said.
"It's a locked room murder."
"That's right."
Conan also nodded and agreed with that statement.
The reason it was a locked room murder was that when we came, the study door was locked.
But of the two keys, one was with the lady who came with us, and the other was with the diplomat, so simply thinking, the culprit couldn't commit the crime and then lock the door and leave.
"Son-in-law, why is it a locked room murder?"
I explained to Kogoro.
"Ah~ I see."
I whispered quietly to Conan.
"Conan, I know who the culprit is, did you figure it out?"
"What? Really?"
"Yeah.
Want me to tell you?"
Conan thought for a moment and then refused.
"No, I'll try to deduce it myself."
"Oh~ Let's see the Detective Boys' skills then?"
"Instead, help me a bit.
Brother, since you're an adult, you can go around here and there easily."
"Sure."
Just then, the forensics team found something strange on the key and reported it.
"Inspector! The key the victim had is a bit strange!"
"What!?"
We went to check the key.
On the key, there was a flat egg-shaped keychain, and the flat part was made to split in two.
"Ah! Isn't this Scotch tape?"
Between the split keychain, Scotch tape was attached, and it looked like something like a string was attached, with a thin line making a raised mark in the center of the Scotch tape.
"Oho~ This is getting interesting."
"Brother, let's go to another room for now."
"Okay."
Conan and I collected evidence by going to several rooms and returned.
Then Heiji appeared triumphantly and said.
"I've figured it out! The locked room trick and who the culprit is."
"What? You solved it already?"
"Yes, it looks like a perfect locked room, but there's one gap."
"A gap?"
"There's a gap under the door!"
"Hahaha, don't tell me you're going to say they threw it through the door gap? That's impossible."
"It's possible.
With Scotch tape and this fishing line with a needle I just found."
Heiji asked Inspector Megure to help for a moment.
"Please play the role of the body for a moment."
"Ah, sure."
Heiji attached a fishing line to the keychain with Scotch tape, used the needle to thread the fishing line into the pocket of Inspector Megure's pants, connecting it.
Then he held the fishing line and the key, went outside slowly, locked the door with the key, and showed a demonstration where he pulled the fishing line connected to the key so the key would automatically go through the gap under the door into the body's pocket.
"Oh! It really went in."
"And finally, if you pull hard, the fishing line comes off the tape, leaving no evidence."
"It really is.
Then who is the culprit?"
"Considering the time it took to commit the crime and finish this trick, the culprit is only the grandfather."
"What!?"
"How about it.
Am I wrong!?"
"Hoohoo, you can't do bad things.
Yes.
It's me."
At that moment, I said.
"That's not it."
"Jin!"
"The trick Heiji mentioned now is impossible."
"What???"