A free Facebook surveillance tool is not something we advocate. This is because free apps are frequently infected with viruses, spyware, and other malware that you don't want on your Mac, PC, or phone (and on their device too). It's much better to pay for a Facebook spy program instead. While monitoring their Facebook activity will cost you some money, you can be assured that when you choose a subscription-based Facebook tracker program, you're choosing something you can trust to keep your information safe.