“I can’t help, there.”
Grover, though, did not pursue the argument. He seemed buried in meditation.
“Here is something we overlooked, too.” He spoke slowly, searching for hints in his own inner processes. “Look at the smoke. The light in that office, according to the picture itself, was the overhead dome. Now, with that small actinic quality, the camera with a daylight type of film, would have recorded only in exposures amounting to at least a second. It would have been possible for the man to have fired, dropped the gun. Possibly if he snatched it up and let it drop—no. The flash would have been filmed! Let’s work at this!
“Notice—the edge of the smoke is duller, less distinct, but the lower part of the smudge is thick and dense, as though—the smoke had been settling during the exposure.”
“So, where does that get us?” asked Ellison.
“To this. The man at the desk is extremely clear. Astrovox is less distinct, recognizable but still a trifle hazy. We assumed it was the smoke. It isn’t. It is the fact that when he heard the shot, Astrovox was just outside the doorway. He ran in, too fast to be recorded in that brief exposure that caught him just pausing. Now, that accounts for the other camera’s proving that a shot was fired.
“It was fired at the man behind the desk. Then Astrovox ran in, and he had to be there an appreciable fraction of time to be registered. He got in just about half-way through the exposure, and his pause imprinted his image just before the shutter closed. Now—what would have been his natural, subsequent procedure?”
Frightened by the past sound of the Voice of Doom, he went on, the man had been about to leave, and was merely waiting for Potts.
“He ran in, saw the source of the shot, saw the man crouched under the desk after his shot had hit the inkwell instead of his mark, the other man. He turned, and ran. But the man who had crouched would know that he had been seen, must think the old man ran for help.
“He went after Astrovox—to silence him!”