The perfect crime

I was stuck in a toxic relationship with my girlfriend so I decided to kill her.
We’d been together since high school, but more and more she’d been going on about how we need to get married now and it was driving me nuts.

But the police are pretty darn good at their job these days, so unless I did it well they’d find some evidence and arrest me.

Obviously there was a lot on my shoulders with the murder and such…

So I decided to call up one of my childhood friends and invited him over to my house. His name was K and he made his living as a famous mystery novelist.

He was a dark and gloomy guy in high school and was often the target of bullying.
Having said that, the ones who bullied him the most were me and my girlfriend, haha. I mean, he was so annoying, haha.

Despite that K greeted me with a smile. It looked like he’d let go of the past, he didn’t even ask about the giant gash across my cheek that I got while arguing. I think it was better if he didn’t ask anyway.

We chatted while drinking some tea, mostly about K’s work.

I asked him about how a mystery writer comes up with their stories, and he smiled and answered me.

“Right now I’m thinking about a story where a man kills his girlfriend. He stabs her to death in his own home. Afterwards he calls the police, telling them that when he returned home he found her dead body lying there like that.”

“But if you kill someone in your own house they can trace that, right? And why would he alert the police about it…?”

“That’s why the criminal is so smart. The police would never expect the criminal to behave so brazenly. So he eliminates himself as a suspect right from the start.”

“Ah, I see. Is there anything else the guy needs to look out for? If he’s aiming for the perfect crime, that is.”

“Hmm. For example, he should buy a knife from the local supermarket with his head held high. If he tries to hide himself then it’s just even more suspicious. He needs to leave his fingerprints all over it. The police would never think they’re his fingerprints and it would mess up the whole operation.”

As you’d expect from a famous mystery author, K’s way of thinking really was different. I decided to kill my girlfriend in the same manner.
As we were about to part I said to him,

“Thank you. I feel so much better having spoken with you.”

Without understanding anything that was going on K smiled at me.

“Not at all. In the end we were just discussing material for a book anyway.”

EXPLANATION

K realised the man was going to kill his girlfriend and in order to get revenge on him told him how to murder someone so he would easily get caught.

That guy really is an idiot.