I would have the city/town/etc come and inspect the building for any issues. I have in many cases gone into buildings and the conditions need to be rectified. Not saying there isn't anything paranormal, but atrocious wiring, mold, etc can have an easy influence if that many are suffering. If no issues are found or detected, then having someone come in and 'cleanse' the building would be justified. Once again, gut feeling on this one lol.
I hope that the fact there are so many protesting will force the property owners to release people from their leases, if they even have contracts. I don't know what type of compensation or help the affected renters can get, except to be able to move.