Informed that my son has been severely bullying kids at his high school, unsure of what to do

Hello,I was advised to post on this subreddit about my situation.My 16 year old son's principal has recently, as in this morning, informed me that my son and a group of his friends have been bullying some kids at his high school. Apparently they have been playing embarrassing and unflattering pranks on theses kids, video taping it, and posting it on instagram on a group account they created. In addition, they have also been taking compromising photos of the victims and posting them, as well as making "memes" using photos of them.Also, they have been caught in class teasing these kids, making crude jokes, to the point where the teacher has to step in and end it. I had been informed of these in class disruptions beforehand, and had disciplined him accordingly. As of now it seems that it did not accomplish anything.What broke the camel's back however is the school's discovery of the instagram account, which has led the principal to informing me of the situation. She also stated that this bullying had led one of the kids to transfer schools and the parents of the victims threatening to sue the school for the damage they had allowed to happen to their kids.I am not exactly aware how long this has been happening, but based on the severity I imagine it must have been happening for quite some time now. Obviously, I am absolutely furious with my son. When he came home from school in the afternoon, I laid into him and demanded to know why he did this, as I previously thought it would not be in his nature to do something so demeaning and cruel. He told me it was all just a joke and was not expecting everyone to take it so seriously, saying it was all just for shits and giggles. When I further questioned him, he said that "those pasty ass white kids were too easy a target to not make fun of". At that point, I decided to talk with him once I cooled down and sent him to his room for the rest of the evening. I have also confiscated his phone for the time being.The principal has asked me to come in tomorrow to further discuss the situation, and the consequences he will be receiving as a result of his actions.I am obviously hoping to add on some discipline on my end, and also would like to find a way from him to understand the gravity of the situation and exactly how as a result his actions has severely negatively impacted his victims and many more people. I want to get that through his skull, as it seems he isn't taking this situation seriously at all. My wife passed away a few years ago, so I am kinda on my own with him.Any advice and help as to how to talk with him, in addition to disciplining him would be much appreciated. via /r/Parenting http://ift.tt/2uShqE0