The night was already far spent, and the expected visitor still delayed.  At length the pale secretary appeared at the door to announce his coming.

Gard rose from his seat, and extended a welcoming hand to gray-haired, sharp-featured District Attorney Field.

Brencherly bowed with awkward diffidence.

Gard’s manner was ease and cordiality itself, but his heart misgave him.  So much depended upon the outcome of this meeting.  He would not let himself dwell upon its possibilities, but faced the situation with grim determination.

“Well, Field,” he said genially, “let me thank you for coming.  You are tired, I know.  I’m greatly indebted to you, but I’m coming straight to the point.  The fact is, we,” and he swept an including gesture toward his companion, “have the whole story of Victor Mahr’s death.  Brencherly is a detective in my personal employ.”  Field bowed and turned again to his host.  “The person of the murderer is in our care,” Gard continued.  “But before we make this public—­before we draw in the authorities, there are things to be considered.”

He paused a moment.  The district attorney’s eyes had snapped with surprise.

“You don’t mean to tell me,” he said slowly, “that you have the key to that mystery!  Have you turned detective, Mr. Gard?  Well, nothing surprises me any more.  What was the motive?  You’ve learned that, too, I suppose?”

“Insanity,” said Gard shortly.

“Revenge,” said the detective.

“Suppose,” said Gard, “a crime were committed by a totally irresponsible person, would it be possible, once that fact was thoroughly established, to keep investigation from that person; to conduct the matter so quietly that publicity, which would crush the happiness of innocent persons, might be avoided?”

“It might,” said the lawyer, “but there would have to be very good and sufficient reasons.  Let’s have the facts, Mr. Gard.  An insane person, I take it, killed Mahr.  Who?”

“His wife.”  Gard had risen and stood towering above the others, his face set and hard as if carved in flint.

Field instinctively recoiled.  “His wife!” he exclaimed.  “Why, man alive, you are the madman.  His wife died years ago.”

“No,” said Gard.  “Teddy Mahr’s mother died.  His wife is living, and is in that next room.”

“What’s the meaning of this?” Field demanded.

“A pretty plain meaning,” Gard rejoined.  “The woman escaped from the asylum where she was confined.  According to her own story, she had kept track of her husband from the newspapers.  Mahr couldn’t divorce her, but he married again, secure in his belief that his first marriage would never be discovered.  Mad as she was, she knew the situation, and she planned revenge.  Dr. Malky, of the Ottawa Asylum, is here.  We sent for him.  The woman has been recognized by Mahr’s butler as the one he admitted.  There is no possible doubt.  And her own confession, while it is incomplete in some respects, is nevertheless undoubtedly true.