Camera's a very good suggestion. My old hood, next door had a system, monitored by a patrol service that phoned when it went off. People had no cell phones. No one answered inside. The wife was an invalid, confined to a w/c. They were close friends of a nascar driver that had recently been murdered. The alarm went off and reset several times.
I saw my neighbors pick-up going down the street like a bat outa hell! After 2nd alarm went off!
Something seemed very odd to me. So, I got my shotgun,went thru the bushes etc with binoculars, saw nothing. Unable to call husband at job sites, they changed all the time. I phoned the sheriff. They came out alright! I also phoned his daughter's, no answers.

The service was able to find a daughter, that was concerned and went to the house. She walked into the open door and found several police officer's walking inside with their guns out!

A small critter chewed the wires! And his pick-up was being driven by another neighbor, that was bringing it back from a repair place. Everyone, lived on 5 acres plus. So, not to close physically. I seldom lock doors. Had mine knocked out 25 years ago, cost $1000.00 to have it fixed the next day, pretty costly. If they want in, they will! And the cops found a house key when they search their big boat!

Now, I live near a home with many barking dogs, no one likes, they keep us up endless hours. I overheard someone saying they planned on doing something to the dogs. But, the camera's created a big problem! They had the camera's in and told everyone and it spread. I personally, do not think they have anything! Camera's cannot be seen from outside! Plus, I was walking my dog and he came out and said, "I saw a flashlight and thought I'd check it out!" Meaning, it must not work at night or does not exist. Either way, it is effective!