She's not paranoid. I grew up in a little town about 75 miles south Phoenix. Had a paper route that meandered down a couple of desert roads. One customer had about 12 Chihuahuas, then a couple of months later she had 11. Then about a year later she had 10. When I would deliver in the pre-dawn hours I frequently saw Coyotes around her house. She had a chain link fence, but they dug under it. They are patient and smart. I've even seen one look both ways before crossing the highway.

Looks like the problem here is with people feeding them. We never had a problem with them attacking people, or even larger animals. Just the occasional chicken or unlucky Chihuajua.