I’m about 3 miles from the crash site. My neighbor was in her house when she heard an odd sound and thought “That sounds like an airplane”.
She walked down the hill and spotted the big smoke plume. About then all sorts of sirens started up. That caught my attention and I figured it was a wreck on the 91. My neighbor came wandering back and told me that she was sure it was an airplane crash, and she came real close to guessing what street it was on.
If a prop came off a piston engine under power, it would have made a distinctive sound, sort of like a zipper being pulled.