The same revolver is used on Julia, Ada, Chester, and Rex. + 

All three sets of footprints have obviously been made by someone in the house for the purpose of casting suspicion on an outsider. + 

The murderer is someone whom both Julia and Chester would receive in their rooms, in negligé, late at night. + 

The murderer does not make himself known to Ada, but enters her room surreptitiously. + 

Nearly three weeks after Chester’s death Ada comes to the District Attorney’s office, stating she has important news to impart. + 

Ada says that Rex has confessed to her that he heard the shot in her room and also heard other things, but was afraid to admit them; and she asks that Rex be questioned. + 

Ada tells of having found a cryptic diagram, marked with symbols, in the lower hall near the library door. + 

On the day of Rex’s murder Von Blon reports that his medicine-case has been rifled of three grains of strychnine and six grains of morphine⁠—presumably at the Greene mansion. + 

The library reveals the fact that someone has been in the habit of going there and reading by candlelight. The books that show signs of having been read are: a handbook of the criminal sciences, two works on toxicology, and two treatises on hysterical paralysis and sleepwalking. + 

The visitor to the library is someone who understands German well, for three of the books that have been read are in German. + 

The galoshes that disappeared from the linen-closet on the night of Rex’s murder are found in the library. + 

Someone listens at the door while the library is being inspected. + 

Ada reports that she saw Mrs. Greene walking in the lower hall the night before. + 

Von Blon asserts that Mrs. Greene’s paralysis is of a nature that makes movement a physical impossibility. + 

Arrangements are made with Von Blon to have Doctor Oppenheimer examine Mrs. Greene. + 

Von Blon informs Mrs. Greene of the proposed examination, which he has scheduled for the following day. + 

Mrs. Greene is poisoned before Doctor Oppenheimer’s examination can be made. + 

The post mortem reveals conclusively that Mrs. Greene’s leg muscles were so atrophied that she could not have walked. + 

Ada, when told of the autopsy, insists that she saw her mother’s shawl about the figure in the hall, and, on being pressed, admits that Sibella sometimes wore it. + 

During the questioning of Ada regarding the shawl Mrs. Mannheim suggests that it was she herself whom Ada saw in the hall. + 

When Julia and Ada were shot there were, or could have been, present in the house: Chester, Sibella, Rex, Mrs. Greene, Von Blon, Barton, Hemming, Sproot, and Mrs. Mannheim. + 

When Chester was shot there were, or could have been, present in the house: Sibella, Rex, Mrs. Greene, Ada, Von Blon, Barton, Hemming, Sproot, and Mrs. Mannheim. + 

When Rex was shot there were, or could have been, present in the house: Sibella, Mrs. Greene, Von Blon, Hemming, Sproot, and Mrs. Mannheim. + 

When Ada was poisoned there were, or could have been, present in the house: Sibella, Mrs. Greene, Von Blon, Hemming, Sproot, and Mrs. Mannheim. + 

When Mrs. Greene was poisoned there were, or could have been, present in the house: Sibella, Von Blon, Ada, Hemming, Sproot, and Mrs. Mannheim. + 