He stated that they  have security and it's a multilevel building and is secure well truth be told mine is a 4 unit and has main door locks and cameras throughout so it's a secure building also and I have to worry about the safety of other tenants it's the same situation as the apartment building and they can do something where as I'm being told to deal with it.

Since then a few suspicious things have gone on around the house, nothing major but enough for me to install surveillance cameras.

You would think that one of those folks would have noticed the cameras throughout the home, then maybe they would have not been so outspoken talking about the bad board in the controller and that it was a remanufactured unit and should have never been put in a new fireplace.

Use a rooter router camera through the inspection hole see if the pipe is even there.

Alarm.com is a new player to the market who has a excellent cloud based system which has a lot of bang for the buck, can intergrate camera systems, energy management, and security all under one platform and easy to manage from anywhere in the world being cloud based. 

Get a professional camera or hire someone.

Is it generally safe with security cameras?

You may want to leave some privacy to your tenants - that builds more trust than cameras and spy software.

I had our maintenance company run a camera down the pipe and it had not broken, at a cost of 150 dollars.Cut to last month, I went to the house because she was moving out and I wanted to put stakes in the ground to keep it from happening again.

Low pay & nowadays everyone is shoving a camera in your face.