Officer Morales and Ethics

When listening to the police officers who came to class, they mentioned that sometimes they will "let off" some people because the crime they are doing really isn't a huge thing, they want to give him a warning, or it's just not too huge of a problem. So what came to my mind was if the idea of morals and ethics come into play when they are deciding whether or not to let others off the hook. I know that the department gives them rules and guidelines on whether or not they should arrest someone or let them go, but do police officers have their own moral or ethical code they stand by. If someone is on parole, getting in trouble for something that's a misdemeanor which could result in him going back to prison, would the officer let him off because he thinks its morally or ethically right?