Arthur discovered that Drebber had been staying at the boarding house of Arthur’s mother and had attempted to abduct Arthur’s sister Alice. As Arthur had angrily chased Drebber into the street and had no alibi for the time of the murder, Gregson took him into custody. However, Lestrade soon arrived to announce that there has been another murder. Intending to question Joseph Stangerson, Drebber’s secretary, Lestrade found him stabbed to death in his hotel room with the word “RACHE” written on the wall. Though Lestrade did not find anything else about the room particularly important, Sherlock realized that the pillbox in Stangerson’s hotel room is the last clue. After obtaining the pillbox from Lestrade, Sherlock tests the two pills on an old dog in the building. The first pill has no effect, but the second pill immediately kills the dog, leading Sherlock to conclude that the pillbox contained one poisonous pill and one harmless pill. Just then, Wiggins, one of the street urchins employed by Sherlock, arrives to tell him that the cab Sherlock wanted was here. Requesting the driver’s help with his luggage, Sherlock summons the cab driver to the room. Catching the driver off guard, Holmes handcuffs him and introduces the driver to the others as Jefferson Hope, the murderer of Drebber and Stangerson.