There is really no point in asking for advice about this here, as it sounds like you need legal advice from a local attorney well aware of the ever-changing marijuana law in Colorado.  

Under Colorado law now, its possible to sell marijuana legally.

I'm over that now.I don't know what the case laws have been, if any, with medical marijuana and what rights medical patients have.

It doesn’t smell quite like marijuana and I know the male tenant smokes but he’s kept it outside, as required by our lease agreement.

Rather peculiar.

You can prohibit marijuana just like you can prohibit alcohol.

I have a policy in my lease that says criminal activity - regardless of where it took place - may be grounds for termination and a conviction is not necessary.Example: Tenant was caught with meth, fentanyl, and marijuana during a routine traffic stop.

Vikram,This post is an editorial all to itself.I have to add to your list of peculiar cities: New Orleans, San Francisco and New York.

There are millions of dollars wasted every year arresting people for smoking something that is only illegal because of a smear campaign years ago.According to the government, marijuana and cocaine are in the same drug category.

Someone may meet a neighbor who offers that they smoke marijuana.