“And whoever came,” Roger was able to fill it all in, now, “with the kangaroo, meant to get into the safe, get the gem, put it in the animal’s pouch, and then, to make it go away safely, he had to turn on the fire alarm that rang a bell, the way it must ring in the act, for the kangaroo’s signal to rescue the rats. It rescued them, and hopped away, to its attendant, just the way it would in the theatre.”
“And what about the film?” asked Doctor Ryder.
“Some was probably in the ‘sound camera’ by the cage. Either in trying to shut it off or in an accidental knock against it by the animal, the ‘continuous’ lever was thrown. Focused with a diaphragm opening to catch the white rats’ movements under a vivid light, the lens got only an under-exposure in the light from the ceiling!”
“Logically,” Grover finished up for his younger cousin, “the man knew the camera had been running. He took out that magazine, took the blank film from the new can to replace it, making as many snaps as had been made of the rats, jarred the continuous-take lever on by accident, giving us the clue of claws-on-glass as his animal came to the cage, with the ringing of the alarm bell.”
“Science to the rescue!” Roger exclaimed. “Now we know it must be the animal trainer who is the key-man. If he did it for his own greed, we can protect ourselves from him in the future.”
“If he was a hired accomplice of others, as I assume to be most likely,” Grover added, “he can be compelled to tell us the facts.”
Declaring that he would interview the man in person, bidding Roger to add to the few hours of sleep secured before their midnight watch, the laboratory head, as the staff began to arrive, urged Doctor Ryder to say little, and to wait until consideration could be given to his plea that they help him get the Eye of Om.
On the emergency couch, in a small combination of rest-and-first-aid room, Roger stretched out without feeling the least bit drowsy.
The excitement was still keeping him alert.
“Science to the rescue,” he mused. “Modern apparatus is wonderful and understanding how it works and what can be done with it ought to help people solve many mysteries. They have developed instruments to measure nerve responses and other things. There is the lie-detector for one device to help fight crime.