Recommended Reading:

How to Catch a Cheating Husband or Catch a Cheating Wife and Put an End to the Lies!

Tactics To Catch Your Spouse Cheating

If you think that your wife or husband is cheating on you,  how can you be sure?
Capture them cheating on camera. That is easy to say, but what camera to catch [...]

A Private investigator often has to spy on someone.
Either physically spying on someone for for insurance or to catch a cheating spouse or investigating someone online for background checks or employment.
Whether you want to investigate for your own purposes or as a career offering your own private investigation services, you will need to use [...]