I know of a few similar places near me
It's a simple premise - find an addict with their own place, and a habit (helps if they're vulnerable). Hole up there and use it as a stash/safe house.

Or, sit round there and invite custom. Gradually it'll become a hive for users, there'll be a few minor busts, then the victim gets evicted and the trade moves elsewhere.
( disasterprone "Pyjamas caused the Holocaust", Mon 20 Sep 2010, 7:22, Reply)