(Part 02 of the 03 parts of the post)

Use a good scan of BlueTooth devices and do it in an environment where the only device in the vicinity is the device doing the scanning. Some rare Bluetooth devices can reach 100 meters of range. Example application on the Android platform:

https://play.google.com/store/apps/details?id=com.aconno.blesniffer

Scan in a situation where there are only people, preferably with a history of vaccination by Pfizer. Look for unnamed MAC and analyze if there might be nearby devices detected in the test. If there are such unnamed MACs without explained origin, the possibility that such signals have human bodies as a source would be relevant.