As they moved to the centre of the open space Graham indicated Bobby’s evening clothes.

“Why are you dressed like that, Bobby?  You did come from town?  You can tell us everything you did last night after I left you, and early this morning?”

Bobby shook his head.  His answer was reluctant.

“I didn’t come from New York just now.  I was evidently here last night, and I can’t remember, Hartley.  I remember scarcely anything.”

Graham’s face whitened.

“Tell us,” he begged.

“You’ve got to remember!” Katherine cried.

Bobby as minutely as he could recited the few impressions that remained from last night.

When he had finished Graham thought for some time.

“Paredes and the dancer,” he said at last, “practically forced me away from you last night.  It’s obvious, Bobby, you must have been drugged.”

Bobby shook his head.

“I thought of that right away, but it won’t do.  If I had been drugged I wouldn’t have moved around, and I did come out somehow, I managed to get to the empty house to sleep.  It’s more as if my mind had simply closed, as if it had gone on working its own ends without my knowing anything about it.  And that’s dreadful, because the detective has practically accused me of murdering my grandfather.  How was it done?  You see I know nothing.  Tell me how—­how he was killed.  I can’t believe I—­I’m such a beast.  Tell me.  If I was in the house, some detail might start my memory.”

So Katherine told her story while Bobby listened, shrinking from some disclosure that would convict him.  As she went on, however, his sense of bewilderment increased, and when she had finished he burst out: 

“But where is the proof of murder?  Where is there even a suggestion?  You say the doors were locked and he doesn’t show a mark.”

“That’s what we can’t understand,” Graham said.  “There’s no evidence we know anything about that your grandfather’s heart didn’t simply give out, but the detective is absolutely certain, and—­there’s no use mincing matters, Bobby—­he believes he has the proof to convict you.  He won’t tell me what.  He simply smiles and refuses to talk.”

“The motive?” Bobby asked.

Graham looked at him curiously.  Katherine turned away.

“Of course,” Bobby cried with a sharpened discomfort.  “I’d forgotten.  The money—­the new will he had planned to make.  The money’s mine now, but if he had lived until this morning it never would have been.  I see.”

“It is a powerful motive,” Graham said, “for any one who doesn’t know you.”

“But,” Bobby answered, “Howells has got to prove first that my grandfather was murdered.  The autopsy?”

“Coroner’s out of the county,” Graham replied, “and Howells won’t have an assistant.  Dr. Groom’s waiting in the house.  We’re expecting the coroner almost any time.”

Bobby spoke rapidly.