I found out yesterday that my neighbor moved out without saying anything so I called him to see what was up. I guess a few weeks ago his fiancé caught the maintainance guy out in the hallway with his ear up to the door and a few days later my friend was talking to his upstairs neighbor and apparently that guy came home one day to find that same maintanace guy in his apartment and he said he was "fixing something." apparently no work order but I don't know the full story there. Anyway it got me thinking about keeping unwanted intruders out. We already keep all our shit locked, and have dowels blocking the sliding door and windows. There's nothing we can do about our actual deadbolt/door so i'm mainly looking for ways to deter someone once they break in (or if maintanance decides to come unauthorized) and a way to alert me or my SO if one of us is home. So in this situation what do you think would be the. Best course of action?