His hand struck the air with an imaginary knife.

I pointed out that he had just drawn the imaginary knife across his own throat.

He demonstrated, an imaginary knife cutting straight down through air.

"I felt like . . ." he said, grasping an imaginary knife and plunging it into his stomach, hara-kiri style.

He lowered his right hand to his side, and half clenched his fist, indicating an imaginary knife.

Officer Scirica told a recruit to stand in the corner, then picked up an imaginary knife, and yelled, "I hate cops, kill 'em all."

"Ils sont tues," he said drawing an imaginary knife across his throat.

I raised my arm with an imaginary knife in it, and brought the arm down in an arc.

He drew an imaginary knife across his throat.

She narrowed her eyes and struck out with an imaginary knife, preparing, she said, "to kill Scarpia like a demon!"