You don't need to own a Ring device, and no subscription fees for just their neighborhood service. See alerts from Ring users in whatever size area you'd like. View a newsfeed for your area or a map, and customize your alerts. Three suspicious events reported within a 3 mile radius from me within the last month, and one crime at a Ring user's next-door neighbor.

Come on, you knew this was coming.  Looks pretty cool, I must say...

Next-Level Autonomously Flying Indoor Security Camera | Ring Always Home Cam 

(Video embedded below in full post)