Level of Difficulty: Easy

Sehun killed his wife for he was not sure of her fidelity. He stabbed her on heart with a knife. To cover up his crime, he pushed her body in his car. He drove a few miles and then threw her body in an alley. He carefully wiped his finger prints and threw the knife on the crime scene.

Then, he drove back to his home. After an hour, he received a call from the local sheriff. The sheriff told him that his wife was murdered and that he must reach at the crime scene. But when he reached the crime scene, he was arrested by him.

How did the sheriff know that Sehun was the culprit?

Solved by ihartkyuhyun, 3rd time in a ROW!

Answer: It is simple. The sheriff never told Sehun where the crime scene was. But still he reached at the right place. This points towards the fact that he knew it already and that he is the killer himself.