Drug use and contacting the police

[Michael Shadow]

I went to one of my apartments today walked in the door and could smell weed. I knew which apt it was coming form so I knocked on the door and asked the tenant if anyone in their apartment was smoking weed, I knew they would deny it but I just wanted them to know that I knew what was going on. They apologized for the smell that was coming form the candles and said it wouldn't happen again.

Anyways so I was wondering if it does happen again and I call the police, could they enter the apartment with just smelling it or would they need more evidence to enter the apartment?