They did know about what type of knife was used.

I mean, how did he get hold of a knife?

I never let go of the knife in my right hand.

Using both hands with all my might I could not make him let go of the knife.

If he let go of the knife, everyone could be friends.

She thought of the knife he had not used the last time.

In a moment I felt the pressure of the knife again.

He's got him a special kind of knife he makes himself, and knows how to use it.

There was a voice, then an image of the knife.

They had issues with the size of the knife and the sound effects used.