At this point in the story, Virginia initially believes that the figure in the Tapestry Chamber is her mother's maid, working in that room as she did on occasion. However, upon further inspection, she realizes that it is the Canterville Ghost, behaving in his typical negative manner (rattling chains, groaning through keyholes, etc.). The exact quote is as follows:
"As she was running past the Tapestry Chamber, the door of which happened to be open, she fancied she saw some one inside, and thinking it was her mother's maid, who sometimes used to bring her work there, looked in to ask her to mend her habit. To her immense surprise, however, it was the Canterville Ghost himself!"