I am looking for the name of an old black and white movie from the 40s, 50s or 60s. It was set in a desert town. The townspeople were injected with something that turned them into robotic or stepford types. The injection site was the back of the neck. I think they were inevitably adducted because a young boy (10-12 years old?) is taken by the aliens. No one would believe him that townspeople disappeared until he disappears.