We have a security system and it can alert us on the phone and anyone in the family could scan the code in for the system and see all of our 8 cameras. 2016. Phone alerts also. It wasn't that expensive and works good, but there's more modern systems with more storage that I'd like to have. I'm not sure if anything else has been mentioned about the W's taking the cameras? DVR/CCTV device?
This article talks about KR cameras. I believe that he might also have received alerts on CR's cameras as well but I don't know for sure.
Security cameras set up inside home of Ohio massacre victim could have helped identify killers | Daily Mail Online