especially when coming down the hill or heavy braking. The noise is only heard just before the car stops, not during braking. I searched but didn't see anything like this. Your advice is appreciated before I take the wheel off and inspect.
I think I fixed the problem. I didn't personally drive the car but my wife said it stopped making the noise. I opened up the caliper's slider pins and they all dried up. I couldn't even move them by hands. They stuck. I had done the rear brakes twice and never bothered to grease these slider pins. The calipers were never fully released but luckily the pads are still about 3/4 of the original thickness (I just changed them out not too long ago).
If they were squealing it probably would have been the sensors but they were creaking so I'd suspected it was the stuck calipers or dried up suspension bushings.