I have suggest some tips for know if someone is spying on my computer mac:
Click on your Apple icon & select Software Update to install software and security updates on your Mac.
Click and Finder and select Applications from your sidebar.
View the installed applications & research any program that looks unfamiliar or suspicious.
Select any application and press Command-Delete to remove the program from you mac.
Press Command-Space & type Activity Monitor and press "Enter."
View the running processes & research any program that looks unfamiliar or suspicious.
Select a process and click "Quit Process" to kill any programs that may be a threat.