Do not confront your tenants directly!

I have had exactly that scenario, confronted the person and it was her parent's dog which she takes hiking regularly.

If she confronts you or your tenants, make sure you record the interaction.

(Actually going to pull the new carpet back along the shared wall and spray foam any gaps under baseboard).I have not confronted the neighbors yet as it is in my experience that smokers in general (especially dedicated ones as they clearly are) do not particularly care and it is unlikely that they would stop anyway.

I'd avoid confronting them about it now.

Thanks....How would you go abut it without direct confrontation? 

I understand there might be hesitation with an immediate increase because this would force out the current tenant or might lead to confrontation, but it's your business to manage.

I'd seriously consider confronting your old accountant and asking for reimbursement of fees and estimated penalties.

A simple non-confrontational conversation with a superior will definitely get this person's attention.  

She first made up a story that the check was mailed...then 8 days later, when been confronted with her lie, she asked the property manager to come over and collect the rent including the late fees.