Quickly end month to month lease w/ potential drug dealer

[Steven Tawresey]

Hey all. So I know we're not lawyers (although if you are one and you think I need one, PM me) and any advice I get should be taken with a grain of salt, however I figure the collective minds here may be able to help with my current issue.

I've got a tenant in a Denver Colorado 4-plex who's been with me for 3 years. I've gotten intermittent complaints of various minor lease violations such as noise, smoking in the house, etc. but none detailed enough to give me verification that this guy is the culprit (by all reasonable assumptions he is). I also just got a complaint from my neighbor that he is dealing drugs in the alley. 

So, it's time for this guy to go. He is on a month to month lease that entails a 30-day notice of termination. I was planning on terminating in April anyways to do renovation on the unit so no big deal. I don't need to give a reason for termination anyways.

So my question is this, is there any way I can get him out sooner given the potential illegal activities, without proof of any of the lease violations/ drug dealing? Eviction would take much longer than 30 days here in Denver so I don't think that's an option.

Anyways, my neighbor is pissed and has stated "he is going to take matters into his own hands." Not sure what this means other than calling the cops (which he should have done anyways) but I'd rather not find out.

Any help you all can give would be very much appreciated. Thanks in advance!