How do I get a roommate out when he is on the lease as well?

There are 3 of us guys, one of them (let's name him Sam) is someone who I have lived with for more than 2 years and it's been awesome. We were best friends before and still are. We just have a great time being in the same place; this things stay clean, quiet, peaceful.

Well another guy (we will name him Hank, although some other choice words come to mind) is someone who has been begging to get a place with us for so long. So we decide to get a 3 bedroom house. At first things were good, but we had two rules before we moved in: keep the house clean and also no drugs in the house what so ever. He has smoked weed in his room more then 10 times and despite us talking to him and asking him to stop he won't. We have decided to move out.

However, I prefer he get out because with college and work I don't have the money nor the time to move. I work at a coffee shop and I asked one of the cops that if we talked to the landlord and she calls the cops on him, would we get charged for drugs since he has them in his room. They said no as long as there wasn't a bong on the coffee table we would be good.

So Sam wants to just move and not explain this to the landlord. My thought is we tell the landlord she evicts him (it says nothing on the lease about why she can or cannot evict him despite all of our names on the lease) or we move out and she loses the rental income. It also does not say on the lease any penalty for us moving out early. The landlord is an older women.

Thanks for your help!