Aaronia Haldorn was his mistress. Joseph was a puppet, in the family as in the Temple.
In San Francisco Fitzstephan and Alice arranged so that he became acquainted with her husband and Gabrielle through other friends of the family. Gabrielle was now a young woman. Her physical peculiarities, which he interpreted pretty much as she had, fascinated him; and he tried his luck with her. He didn’t have any. That made him doubly determined to land her: he was that way. Alice was his ally. She knew him and she hated the girl–so she wanted him to have her. Alice had told Fitzstephan the family history. The girl’s father did not know at this time that she had been taught to think him her mother’s murderer. He knew she had a deep aversion to him, but did not know on what it was based. He thought that what he had gone through in prison and since had marked him with a hardness naturally enough repellant to a young girl who was, in spite of their relationship, actually only a recent acquaintance.
He learned the truth about it when, surprising Fitzstephan in further attempts to make Gabrielle–as Fitzstephan put it–listen to reason, he had got into a three-cornered row with the pair of them. Leggett now began to understand what sort of a woman he was married to. Fitzstephan was no longer invited to the Leggett house, but kept in touch with Alice and waited his time.
His time came when Upton arrived with his demand for blackmail. Alice went to Fitzstephan for advice. He gave it to her–poisonously. He urged her to handle Upton herself, concealing his demand–his knowledge of the Leggett past–from Leggett. He told her she should above all else continue to keep her knowledge of Leggett’s Central American and Mexican history concealed from him–a valuable hold on him now that he hated her because of what she’d taught the girl. Giving Upton the diamonds, and faking the burglary evidence, were Fitzstephan’s ideas. Poor Alice didn’t mean anything to him: he didn’t care what happened to her so long as he could ruin Leggett and get Gabnielle.
He succeeded in the first of those aims: guided by him, Alice completely demolished the Leggett household, thinking, until the very last, when he pursued her after giving her the pistol in the laboratory, that he had a clever plan by which they would be saved; that is, she and he would: her husband didn’t count with her any more than she with Fitzstephan. Fitzstephan had had to kill her, of course, to keep her from exposing him when she found that his clever plan was a trap for her.
Fitzstephan said he killed Leggett himself. When Gabrielle left the house after seeing Ruppert’s murder, she left a note saying she had gone for good. That broke up the arrangement as far as Leggett was concerned. He told Alice he was through, was going away, and offered of his own accord to write a statement assuming responsibility for what she had done. Fitzstephan tried to persuade Alice to kill him, but she wouldn’t. He did. He wanted Gabrielle, and he didn’t think a live Leggett, even though a fugitive from justice, would let him have her.
Fitzstephan’s success in getting rid of Leggett, and in escaping detection by killing Alice, encouraged him. He went blithely on with his plan to get the girl. The Haldorns had been introduced to the Leggetts some months before, and already had her nibbling at their hook. She had gone to them when she ran away from home. Now they persuaded her to come to the Temple again. The Haldorns didn’t know what Fitzstephan was up to, what he had done to the Leggetts: they thought that the girl was only another of the likely prospects he fed them. But Doctor Riese, hunting for Joseph in Joseph’s part of the Temple the day I got there, opened a door that should have been locked, and saw Fitzstephan and the Haldorns in conference.
That was dangerous: Riese couldn’t be kept quiet, and, once Fitzstephan’s connection with the Temple was known, as likely as not the truth about his part in the Leggett riot would come out. He had two easily handled tools–Joseph and Minnie. He had Riese killed. But that woke Aaronia up to his true interest in Gabrielle. Aaronia, jealous, could and would either make him give up the girl or ruin him. He persuaded Joseph that none of them was safe from the gallows while Aaronia lived. When I saved Aaronia by killing her husband, I also saved Fitzstephan for the time: Aaronia and Fink had to keep quiet about Riese’s death if they wanted to save themselves from being charged with complicity in it.