I've always been afraid of leaving home only to come back to ruins, but a recent incident has opened up a frightening possibility of retaliation by some shady unrelated individuals against our home over a complicated dispute (or at least it seems that way to me)

The family member I share the house with considers the matter settled and is nowhere near as concerned. They outright refuse to allow me to install security cameras, saying I am overreacting. 

I can't seem to shake the fear that these people will target our home while we are out. We live in a quiet suburb with plenty of neighbors and light traffic but I'm not really sure what I can do to alleviate my feelings. Our home contains our lives and the thought of it being destroyed while we are away is keeping me up at night. What can I do about this?