DEATH RAY STOPS MOTOR (May, 1929)
I’m going to go with complete fraud. I don’t even know if an EMP would stop a 1920′s vintage motorcycle.
More on Harry Grindell Matthews the so-called copier of the “Death Ray”
DEATH RAY STOPS MOTOR
USING portable apparatus weighing less than 50 pounds, the inventor of the so-called “death ray” recently succeeded in stopping the motor of a motorcycle by directing the deadly rays into the vitals of the engine. The photo below shows him just after completing his successful demonstration. He is A. Roberts of London, England. Mr. Roberts claims to be the original inventor of the death ray which he showed to H. Grindell Matthews, who won considerable newspaper publicity through his efforts to dispose of the ray to leading governments for purposes of warfare. The death ray has electricity as its basis, but the inventor refuses to disclose just how he produces his mysterious effects.