I just read about this on the Wikipedia page for the original Omen. Apparently, in 1974 there was an episode of Kolchak: The Night Stalker, in which a devious person was running for public office, and we gradually learn that he is some kind of agent of Satan. It has scary Rottweilers, people having horrible accidents as soon as they come into any kind of conflict with the devil's pawn.... the whole enchillada. Anyway, apparently Den of Geek noticed the parallels with The Omen. I can't remember ever hearing about this connection in my entire life, but it sounds like it must be one of the main inspirations for The Omen. It had to be. Anyway, the episode was called The Devil's Platform, if you feel like doing some googling of your own. Here are a couple of videos about it: