Our coyotes back east are also called ‘brush wolves’ - and are more wolf size than the western coyote. They are VERY shy of humans and you will seldom see them in the wild.
Since they did not get one of these animals to examine, I wonder if they might have been wild dogs - which are known to be vicious and do often attack humans.
I live in a “rural” area in the midwest. I shot and killed a coyote in my backyard earlier this year. I presumed he was hunting my Beagle pups which happened to be inside when he came trotting into our yard middle of the day.
Coyotes are predators, as such, unless in desperate situation will hunt and attack anything that is reasonably low risk for them to kill. Not sure why they would attack a full grown gal, but I do not doubt the story.
Predators such as coyotes are not cowards, as someone posted above, they have to be very careful of being injured as an even relatively minor injury can result in their inability to kill and therefor eat. A broken leg is a death sentence. A bad sprain can also be a death sentence for a predator.