So, Rab Crane thought, someone else had visited Doctor Alph's house tonight, ahead of him. Probably some other interplanetary spy trying to get the Venusian scientist's deadly secret for his own world just as Crane was trying to get it for Earth.
Had the other spy got it?
Crane's heart went cold with apprehension at the thought. He straightened from examining the dead guard and moved quietly down the dark hall. He had no fear of the beam-web now. He realized that whoever had been ahead of him had cut off the whole protective system.
He went around a corner of the hall and almost stepped on two more dead Venusians. They, too, had been strangled by clutching fingers that had snapped their necks like pipe-stems. Why hadn't they beamed the killer with their guns when he attacked them?
The door of the laboratory was wide open. Inside, all was dark and deadly still. But instinct warned Crane against showing a light as he stepped into the room. He stopped, his eyes trying to penetrate the darkness. Then a smell came to him that made the heir rise along the back of his neck.
The smell of fresh blood! It came from the darkness at his right. Crane flicked on the tiny ray of his ring-light, swung its beam to the floor. Another body! And one glance at the distorted face told him who it was.
The Venusian scientist's neck had been broken like those of the guards. But his head had been smashed also into a bloody red mass. His massive face, comparatively undamaged, stared upward in the beam of light, horribly contorted.
Then Rab Crane's stunned mind perceived something and instantly comprehended its pressing significance. The blood pool from the shattered skull of Doctor Alph was still widening along the floor! That meant that it had been no more than a few moments since the killer had been there!
The killer must still be in the house! Rab doused his little light and sprang to his feet. But the realization had come too late.
In the darkness behind him a harsh voice said, "Kill him!"