Why not put a sensor for all of the above? Seems like the obvious thing to do for information safety reasons, as well as health reasons.

The only situation where it wouldn't make sense to do this is if we already knew the cause, and it was something we had built.

It's suspected to be microwaves so maybe a SDR that sweeps all wavebands with antennas placed aroud windows should be a good starting point?

right ... wouldn't they need to at some point start narrowing things down?