and the blood soaked through it, but curiously there is no bloodstain on the floor under the drugget. However, there is one under the opposite edge of the carpet. It can only mean that the constable guarding the crime scene has been foolish enough to let someone in and leave them alone while they moved things in the room, including the carpet. Holmes tells Lestrade to take the constable to a back room and obtain a confession, which he does vigorously. Meanwhile, Holmes pulls the unfastened carpet aside and quickly finds a hiding place in the floor, but it is empty. The errant constable tells Holmes that the unauthorized visitor was a young woman. She apparently fainted at the sight of the blood but had left while the constable went out to fetch some brandy to revive her. As Holmes is leaving Lucas's house, he shows the constable a photograph, and he recognizes it as the visitor. Holmes goes to the Hope household and confronts Lady Hilda, accusing her of the theft. At first, she denies everything, but is forced to admit her wrongdoing under the threat of certain scandal. Lady Hilda admits Lucas was blackmailing her with a compromising letter written by her years earlier, and demanded the document as payment (an unnamed spy had made Lucas aware of the document). Lady Hilda went to Lucas's house to do the business when, as it happened, his wife from Paris showed up and confronted him about his affair, believing Lady Hilda was his mistress. Lady Hilda hurriedly left. However, she returned to fetch the stolen document after her visit to Holmes convinced her she needed to do so. She hands the document to Holmes. At Holmes's suggestion, the document is put back in the dispatch box using Lady Hilda's duplicate key. When Hope arrives back home with the Prime Minister, Holmes pretends to believe that the evidence has convinced him that the document must still be in the box, shuffled between other papers. It is soon found, and Hope rejoices that it was apparently only a mistake. The Prime Minister suspects Holmes knows more than he is telling, but Holmes responds, "We also have our diplomatic secrets." Background This case was first mentioned in "The Adventure of the Naval Treaty". In "The Naval Treaty", Watson says that this case has "interest of such importance and implicates so many of the