“A suggestion?” asked Cronin. “A suggestion that I do a little blackmailing myself....” “Blackmailing yourself?” Sampson stared. “I don’t see the point.” “Trust Ellery to make a point that on the surface is obscure,” retorted the Inspector. “I saw at once that the only course left open to me was to _manufacture_ evidence!” Both men frowned in puzzlement. “It’s simple enough,” said Queen. “Field was killed by an unusual poison. And Field was killed because he was blackmailing Barry. Wasn’t it fair for me to assume that if Barry were suddenly blackmailed on the identical score, he would again use poison—and in all likelihood the _same_ poison? I don’t have to tell you that ‘Once a poisoner always a poisoner.’ In the case of Barry, if I could only get him to try to use that tetra ethyl lead on somebody else, I’d have him! The poison is almost unknown—but I needn’t explain further. You can see that if I caught him with tetra ethyl lead, that would be all the evidence I needed. “How to accomplish the feat was another matter.... The blackmail opportunity fitted the circumstances perfectly. I actually had the original papers pertaining to Barry’s parentage and tainted blood. Barry thought these destroyed—he had no reason to suspect that the papers he took from Field were clever forgeries. If I blackmailed him he was in the same boat as before. Consequently he would have to take the same action. “And so I used our friend Charley Michaels. The only reason I utilized him was that to Barry it would seem logical that Michaels, Field’s crony and bully and constant companion, should be in possession of the original papers. I got Michaels to write a letter, dictated by me. The reason I wanted Michaels to write it was that possibly Barry, through association with Field, was familiar with the man’s handwriting. This may seem a small point but I couldn’t take any chances. If I slipped up on my ruse, Barry would see through it at once and I’d never get him again. “I enclosed a sheet of the original papers in the letter, to show that the new blackmailing threat had teeth. I stated that Field had brought Barry copies—the sheet enclosed proved my statement. Barry had no reason in the world to doubt that Michaels was milking him as his master had done before. The letter was so worded as to be an ultimatum. I set the time and the place and, to make a long story short, the plan worked.... “I guess that’s all, gentlemen. Barry came, he had his trusty little hypodermic filled with tetra ethyl lead, also a flask—an exact replica, you see, of the Field crime except for locale. My man—it was Ritter—was instructed to take no chances. As soon as he recognized Barry he covered him and raised the alarm. Luckily we were almost at their elbows behind the bushes. Barry was desperate and would have killed himself and Ritter, too, if he’d had half a chance.” There was a significant silence as the Inspector finished, sighed, leaned forward and took some snuff.