“Two days ago,” the detective went on quietly, “old Mr. Blackburn came to the court house in Smithtown and asked for the best detective the district attorney could put his hand on.  I don’t want to blow my own trumpet, but I’ve got away with one or two pretty fair jobs.  I’ve had good offers from private firms in New York.  So they turned him over to me.  It was easy to see the old man was scared, just as his niece says he was last night.  The funny part was he wouldn’t say definitely what he was afraid of.  I thought he might be shielding somebody until he was a little surer of his ground.  He told me he was afraid of being murdered, and he wanted a good man he could call on to come out here to the Cedars if things got too hot for him.  I can hear his voice now as distinctly as if he was standing where you are.

“‘My heart’s all right,’ he said.  ’It won’t stop awhile yet unless it’s made to.  So if I’m found cold some fine morning you can be sure I was put out of the way.’

“I tried to pump him, naturally, but he wouldn’t say another word except that he’d send for me if there was time.  He didn’t want any fuss made, and he gave me a handsome present to keep my mouth shut and not to bother him with any more questions.  I figured—­you can’t blame me, Mr. Graham—­that the old boy was a little cracked.  So I took his money and let it go at that.  I didn’t think much more about it until they told me early this morning he lay dead here under peculiar circumstances.”

“Odd!” Graham commented.  “It does make it more like murder, Howells.  But he doesn’t look like a murdered man.”

“When you know as much about crime as I do, Mr. Graham, you’ll realize that murders which are a long time planning are likely to take on one of two appearances—­suicide or natural death.”

“All right,” Graham said.  “For the purpose of argument let us agree it’s murder.  Even so, why do you suspect young Blackburn?”

“Without a scrap of evidence it’s plain as the nose on your face,” the detective answered.  “If old Blackburn had lived until this morning our young man would have been a pauper.  As it is, he’s a millionaire, but I don’t think he’ll enjoy his money.  The two had been at sword’s points for a long time.  Robert hated the old man—­never made any bones about it.  You couldn’t ask for a more damaging motive.”

“You can’t convict a man on motive,” Graham said shortly.  “You spoke of evidence.”

“More,” the detective replied, “than any jury in the land would ask.”

Bobby held his breath, shrinking from this information, which, however, he realized it was better he should know.