MichaelHarris259

simply yes

There are very few cameras having battery backups inside it as long as you are concerned about cameras without internet then only cameras with DVR and monitors will do the work. Remotely accessed cameras don't work without internet for it needs high speed to upload stream.

Whats already done cannot be undone but for the rest of activities Surveillance system is the best choice. You can go for DIY systems or hire ADT for the purpose.