Through the glass door Rosario was plainly visible, his sleekness ruffled, his white face distorted with terror.

The hand of some unseen person was gripping him by the throat, bearing him backwards.

There was a shout and they both saw the cloakroom attendant spring over his counter.

Something glittered in the dim light--a flash of blue polished steel.

There was a gleam in the air, a horrible cry, and Rosario collapsed upon the floor.
Arnold, who was already on his feet and half-way to the door, caught one glimpse of the upstretched hand, and all his senses were thrilled with what he saw.