"Officer Kim, can I ask for your help to check their belongings once again? This time for the poison reaction," Taehyung asked Officer Kim who was apparently still crouching down next to the corpse, examining something that I didn't know well about. Looking at how focused he was made me feel guilty that we somehow interrupted his work.

"Of course, I'll tell you the result as fast as I can." Opposite from my expectation, Officer Kim accepted our request with a smile. He stood up, gave a quick bow at us, which we replied instantly with a deeper bow, and walked away to retrieve the belongings.

"Okay, one work done. Now let's find out the motive, shall we?" Taehyung jerked his head towards the kitchen, where the interrogation was held.

I smiled and nodded, following his steps.

Inspector Kim had already been sitting face to face with the father when we arrived inside the kitchen. The interrogation had just started and our timing was perfect. We heard the first question asked as we stepped inside the door. The kitchen was spotless, as expected from the elite Byun Apartment cleaning management. Even the kitchen tools were arranged neatly in the racks. It was also rather spacious for a kitchen. A few more dining tables would have fit the empty area, but there's only one of them and it's where Inspector Kim and the father were sitting.

About an hour later, the three people were done with the questioning and Inspector Kim, Detective Do, Taehyung, and I were left alone in the empty kitchen. We listened to the whole interrogation closely, but there seemed to be nothing wrong in any of their statements. The parents and the girlfriend had good relationship with the victim. No one had grudges against him. But, we wouldn't know if there's one of them who had lied to us.

The four of them were also loyal customers of this restaurants and they always ordered beef steaks. That meant all of them knew precisely that this restaurant always gave away butter packets for free along with the breads as appetizer. Any of them could prepare the murder. The motive unfortunately still remained a mistery.

Detective Do suddenly appeared from behind the door. He startled me so bad that I almost jumped. I didn't know why but it felt like it had been a long time since we had last met. My suspicion was growing even more with his seldom appearance. What was he up to lately?

It seemed our questioning look towards Detective Do initiated Inspector Kim to tell the reason why he had come here. "Thanks for coming, Detective Do. We need your help. What did you find?" Inspector Kim asked.

"I did a search about Kim Jongdae's girlfriend, Son Seungwan, at our archive as you have asked for. I found out that her parents were killed in a tragic accident six years ago. Their car collided with an expensive sport car, newly bought, driven for the first time when the accident happened. The name of the sport car driver wasn't mentioned, because the driver was still a minor and there's a policy not to publish the names for minors. The victim, Kim Jongdae, was a minor six years ago. There's a possibility that he was that sport car driver," Detective Do shared his investigation.

"Good." Inspector Kim looked satisfied with his work. "Now, can you find out if Kim Jongdae's family really owned that car six years ago? The license plate was published, right? It should be able to tell you everything."

Detective Do nodded and went out from the kitchen to do what Inspector Kim had ordered.

"Now, we only need an evidence," Inspector Kim said.

A sudden knock on the door pulled our attention away from our conversation. Inspector Kim allowed the door knocker to come in. The door was opened, revealing Officer Kim. He shouted out excitedly as he stepped inside, "Detective Lee! Detective Kim! The result has come out! We found a reaction of the poison!"

"What is this about?" Inspector asked us out of curiosity.

Taehyung grinned. "You said we need an evidence, right? Well, we've got it covered."

The four of us came out from the kitchen, following Officer Kim who trotted joyfully as if he had just won a lottery. He led us to an empty dining table which was temporarily used as a place to test the poison reaction. All the suspects belongings were displayed on it, including Mr. Kim pants. Thankfully, they gave him spare pants to wear.

Officer Kim picked up a black handbag belonged by Son Seungwan. "We found a positive reaction from this handbag, which is owned by one of our suspects, Son Seungwan. It's a solid evidence."

The parents and our friends in the restaurant instantly darted their eyes towards Son Seungwan in disbelief. She looked really flustered with the revelation. She shook her head hard to defend herself. "I'm not the killer," she repeated shakily.

Detective Do then approached us. "I've confirmed the ownership of the car. It's indeed listed under the name Kim Jaewon, Kim Jongdae's father."

"Well, it's settled then." Inspector Kim took out his handcuffs from his pockets and put them on Son Seungwan's hands. "You're under arrest for the murder of Kim Jongdae. You have the right to remain silent. Anything you say can and will be used against you in the court of law. You have the right to an