How to use "unknown" in a sentence

This was a new, unknown type of murder, which they could not understand

On Friday November 30th Druitt lost his job at a private school for some unknown reason

He told her that the money came from a man who preferred to remain unknown

The light of an unknown world was shining brightly in his eyes.

There were a few words in an unknown handwriting.

Certainly, the unknown person who was harassing Tina might have violent intentions

But in this unknown organization, in this secret and incomparably cozy place, he thrived.

In the evening many people came hurrying along the road near their stopping-place, escaping from unknown dangers and going in the direction from which my brother had come.