I always watch in tv shows about undercover cops who mixed with
the secret society to find out more information about them
Than they are not allowed to tell anybody that they are undercover
cops, even their parents, wife etc also cannot tell them. So their
parents etc will also think that they are secret society members
when they are actually undercover cops.
Than only their superior know that they are undercover cop. The
rest of the police force also don't know.
Than I also watch like secret society send people to the police
force to work as policeman so they can provide information to the
secret society about the police 
How true is all these?
