HELP ME TO FIX THIS…….

HI everybody..I’m a system admin in a small company and I want to know what my employees are doing without my presence and when im in office .Ive heard that these is some hidden camera software that can be installed in clients computer and can view what they are doing but i cannot find one with a security which i can apply in my network.Kindly help me with this.waiting for replies and thanks in advance.