He stared after them until they were lost in the crowd, feeling confident that the motion of those white-gloved fingers was meant as a signal of warning.

To whom was it conveyed?
He glanced aside at the jam of figures in the doorway.

Both the black-whiskered man and Connors had disappeared.

It _was_ a signal then, instantly understood and obeyed.
The Sergeant had scarcely grasped this fact when his attention was diverted by the appearance of Miss McDonald.

She was dancing with a civilian, an immaculately dressed individual with ruddy, boyish face.
His intense admiration of his partner was plainly evident, and the girl, simply dressed in white, her cheeks flushed, her dark eyes bright with enjoyment, set Hamlin's cool nerves throbbing.