She is still looking when she feels a second puff of air, stronger and more definite. If the house were less well maintained, she might put it down to a gust of wind outside. If she were in one of the proper rooms she might not have felt it at all. But to her, here in the corridor, that brief pressure is distinctive: the compression as a door somewhere is opened and closed. Except that this is a crime scene secured by the Witness, and she is the investigating officer. There should be no one here without her direct permission.