mystérieux in English:

They found a mysterious city in ruins in the desert.

A mysterious legend has been handed down about this lake.

Smart Alec, who is a private investigator, tried to solve the mysterious murder of a prominent businessman.

The heart's mysterious.

Do you remember the mysterious murder?

Comments have a mysterious way of getting lost in the vastness of Tatoebastan.

The human body has a mysterious power to keep itself healthy and sound.

It casts mysterious shadows on the wall.

Our smile, which is understandable in the context of Japanese culture, sometimes causes a lot of confusion and is notorious among foreign people as a mysterious smile.

On a nice spring day, when Jan was digging in the sandbox in the backyard, he found a small box. In the box was a shining switchblade with a mysterious inscription.

He was a mysterious man. He used to go out every evening and come back in the morning.

They are investigating the mysterious disappearance of a young man.

The man you described, enigmatic, mysterious.

several mysterious events happened which no-one had ever been able to explain.

Several people reported seeing mysterious lights in the sky.