"So look at the murder itself. The pattern. You'll admit it does seem odd and misplaced for these times—or hadn't you noticed?" Beardsley leaned forward sharply. "But it strikes a familiar note with me! Absolutely nothing in the way of material clues; not even the weapon; and the modus operandi is one I haven't seen employed in years, the old idea of the most direct and simple murder being the safest!"
"I—I guess I just don't follow you."
"I mean the way Carmack was struck down. Nothing cute and fancy, no frills or improvisation—just the proverbial blunt instrument, after which the killer simply walked out of there. Believe me, I know about these things. The very simplicity is the killer's protection. You can bet no trace will ever be found of that blunt instrument, and naturally he left no evidence coming or going. But then," Beardsley said obliquely, "your so-called 'Survey' men made a horrible botch of the scene. In '60 we'd have sent them back to patrolling the freeways!"
Mandleco started to protest, then closed his mouth quickly. "I see, I see."
"I can understand," Beardsley murmured, "how emphasis on basic groundwork has become minimized. So much reliance on Indexes and thalamic-imbalance and chart-sifts! It was only a matter of time until a criminal, a really clever one, saw through the system—and reverted." His fingers drummed the chair arm, then he looked up sharply. "And yet of all places, I'd say that Carmack's estate was least ideally situated for this type of murder; you know what I mean? You've been there?"
"Well, I—there have been occasions. Yes."
Beardsley nodded. "I refer to Carmack's elaborate system against invasion of his privacy. To put it bluntly, he had enemies, and his estate was designed as a refuge against those enemies; electronic barriers pitched at ultra-frequency to respond only to certain neural vibrations. Must have taken years of research to come up with that!"
Mandleco shifted impatiently. "Of course, but look here, Beardsley—"
"So it leaves me right where I started, doesn't it? And yet I know this: it was no emotional killing. It was all coldly planned. The killer was someone Carmack trusted enough to have in his home; they were probably having a quiet little chat together. And then precisely—on a predetermined minute—the killer rose from his chair and struck."
Mandleco lifted his heavy hands and then, as if conscious of them, let them fall limply across the desk. "But—come now, Beardsley! Psychologic deduction is all very well, but how can you possibly know that?"