Duplex came with Drug Dealers

[Chris Heeren]

I just purchased my first Upper/Lower Duplex and have 3 tenants in the upper unit. I have been renovating the lower the last few weeks and am almost ready to rent the 3 Bedroom place out. The upper tenants are nice/friendly kids who have been living there for 2 years and have always paid their rent on time and great to deal with. However, as I have been working there the last several weeks, the common area's constantly smell like pot and during an entire day 20-30 people will come and leave the property at various times. Some sneak around the back entrance and tip toe up the stair-well. I have also seen some people leave with glass jars of which I couldn't see the contents, though they do have about 4-5 cases of empty glass jars in their storage area.

I'm looking for advice on how to deal with this scenario? If I evict them before I have a tenant on the lower level I'm stuck paying all the bills through out the winter. What grounds do I have to send an eviction notice other than the smell? I was thinking of sending them a warning/complaint message about the amount of traffic going in and out of the property? Any advice would be appreciated!