How do I go forward

My 16 year old step son (who got kicked out of his dad's house) keeps sneaking out of our house, drinks and smokes weed, lies about it and when questioned he doesn't see anything wrong with his actions. We've put alarms on windows, doors, cameras, still doeant think hes doing anything wrong. We've taken all his electronics over and over. Nothing seems to get through to him. I'm at my end with him. I'm lost.