This text, translated from their language, was found in a crashed Invader ship outside of Pittsburgh, PA. I was lucky enough to enter and grab some containers of their material minutes before the craft auto-vaporized. This passage is particularly relevant:
The sixth principle of suppression–scare them–is an effective means of stopping the humans express themselves or evolve. It is simple and surprisingly effective. Choose one of the things that humans are scared of and that their media likes to report on. Two useful themes are terrorists (or attacks by some form of supposed enemy) and inclement weather (snow being the favorite, known as “the white stuff”). Although we can easily create snow, the former has a more sustained and powerful effect. By spreading intense fear of the enemy the humans’ lower instincts will dominate. They will rally together against the perpetrators of the perceived threat and their mental energy will be consumed in this non-productive blind-alley. Pay no attention to the improbability of this threat or the absence of data to support its credibility. Engaging fear suppresses human rationality and leaves them completely unable to see the real danger. It is our most effective weapon.