camera detecting motion, but showing nothing..

Oh boy.....let's start at the beginning. First we have to look to the Natural, before the Supernatural.( I would check to make sure there is no toxic mold in your room). Now, when the fire department came, what DID they find? Was there damage? Did they find any accelerant? Did a Fire Inspector come & investigate? While you are examining the natural, there is no reason why you cannot attempt to protect yourselves on a different level.

I would smudge the house with White Sage (available in any Health Food Store, or Metaphysical Shop), just remember to undo the smoke alarms first, as the smoke from the sage can set them off

If that does not help, contact a local Unitarian Church, and see if they can get a Paranormal Team to come out & start monitoring the activity.

Remember, any good paranormal team will not charge you for their services, only their travel expenses.

I am a paranormal investigator, and I would love to help you, but unfortantely, I am in a different state.

Please keep us informed, and message me privately, if I can help you in any way.