What security do you use when Rehabbing property?(w/ no WIFI)

[Andrew McGibbon]

Im a week into my first BRRRR on a fourplex and just got a call from the police that they caught a guy breaking into my fourplex. It is completely vacant and currently being renovated. The units are not livable for another few weeks so getting people in them is not an option at the moment. What security system can be used so I can monitor activity there? Ive also seen some motion sensors that just blast a really loud siren when sensing motion and if I tell the neighbors to call the police if they hear it, that can cause a distraction enough to make people leave? I'm not sure what options I have that can provide good security without having access to WiFi. Thanks for your help everyone!