As it shot home a chink of the door opened.

At the same moment Rudolf's hand slipped from Bauer's arm.

With a swift movement he caught the fellow by the nape of the neck and flung him violently forward into the roadway, where, losing his footing, he fell sprawling face downwards in the mud.

Rudolf threw himself against the door: it yielded, he was inside, and in an instant he had shut the door and driven the bolt home again, leaving Bauer in the gutter outside.

Then he turned, with his hand on the butt of his revolver.