So how did they know how to find her there
A dead body will make itself apparent to any passerby by about a week, depending on the ambient temperature. Even if on the otherside of a wall.
However, I have to think the local denizens of the area must have known sooner there was a dead woman there and may have been passing along information.
I don't recall if LE has related EXACTLY how they were notified of a body being there. I mean, EXACTLY who told them.
The sniffer dog would be because someone might have reported the odor.