I've found out recently that a few people in my company do drugs.
Not at work, obviously, but they do it regularly outside of work. If they have done it outside of work, then I wouldn't know about it.
One of these people is a very very close friend, and it's no secret that we are good friends
Do I need to report? Drugs are strictly forbidden in our employee contracts. If it came to be known that I knew, and didn't say anything, I might get into trouble...
Part of me thinks that it's off work premises so it's none of my business