Jaybird1980
Grandmaster
Also add some cameras with a uninterruptible power supply that will allow recording after the power is cut.There have been alerts through the jewelry store networks via DMP, one of the alarm manufacturers I work with. here is what they are recommending because what you saw is exactly what they are doing to them. cutting power and phone is the first step to disable the alarm system. (except the alarm panels have a battery so it still works. And the cellular backup will still phone home even if they cut the phone lines.
Setup central station alarm alerts for power outages, set to dispatch PD for an outage. Most agencies dont mind, and if they are rolling to your location will see the neighborhood is dark and do a simple drive by while they are there. No hits/fines for a false alarm because they realized what was up and didnt expend any serious manpower on the run. They are understanding this is a new-ish tactic.
And if you dont have a centrally monitored alarm, PM me. I know a company. What they did will not stop a properly installed alarm from calling home.