“What are you driving at?” Robinson snapped.

“These crimes,” the doctor answered, “have all the elements of a ghostly impulse.”

Robinson’s laugh was a little uncomfortable.

“The Cedars is a nice place for spooks, but it won’t do.  I’ll be frank.  Howells telephoned me.  He had found plenty of evidence of human interference.  It’s evident in both cases that the murderer came back and disturbed the bodies for some special purpose.  I don’t know what it was the first time, but it’s simple to understand the last.  The murderer came for evidence Howells had on his person.”

Bobby couldn’t meet the sharp, puffy eyes.  He alone was capable of testifying that the evidence had been removed as if to secrete it from his unlawful hand.  Yet if he spoke he would prove the district attorney’s point.  He would condemn himself.

“Curious,” Graham said slowly, “that the murderer didn’t take the evidence when he killed his man.”

“I don’t know about that,” Robinson said, “but I know Howells had evidence on his person.  You through, Coroner?  Then we’ll have a look, although it’s little use.”

He walked to the bed and searched Howells’s pockets.

“Just as I thought.  Nothing.  He told me he was preparing a report.  If he didn’t mail it, that was stolen with the rest of the stuff.  Rawlins’s right.  He waited too long to make his arrest.”

Again Bobby wondered if the man would bring matters to a head now.  He could appreciate, however, that Robinson, with nothing to go on but Howells’s telephoned suspicions, might spoil his chances of a solution by acting too hastily.  Rawlins strolled in.

“The two women were asleep,” he said.  “The old man knows nothing beyond the fact that he heard a woman crying outside a little while ago.”

“I don’t think we need bother about the back part of the house for the present,” Robinson said.  “Howells’s evidence has been stolen.  It’s your job to find it unless it’s been destroyed.  Your other job is to discover the instrument that caused death in both cases.  Then maybe our worthy doctor will desert his ghosts.  Mr. Blackburn, if you will come with me there’s a slight possibility of checking up some of the evidence of which Howells spoke.  Our fine fellow may have made a slip in the court.”

Bobby understood and was afraid—­more afraid than he had been at any time since he had overheard Howells catalogue his case to Graham in the library.  Why, even in so much confusion, had Graham and he failed to think of those tell-tale marks in the court?  They had been intact when he had stood there just before dark.  It was unlikely any one had walked across the grass since.  He saw Graham’s elaborate precautions demolished, the case against him stronger than it had been before Howells’s murder.  Graham’s face revealed the same helpless comprehension.  They followed Robinson downstairs.  Graham made a gesture of surrender.  Bobby glanced at Paredes who alone had remained below.  The Panamanian smoked and lounged in the easy chair.  His eyes seemed restless.