Unauthorized Tenant - Question

[Lisa Wilson]

Hello,

I have a townhouse that was rented to a couple. One individual has moved out. I created a new lease effective June 1st with just the one person. 

I have a suspicion that she has or will get another roommate. The person would not be on the lease. I plan on doing a quarterly inspection, and if/when I find that both bedrooms look occupied,  I'll ask the question. 

What if the tenant says, no, there is no one else living there or it's just someone visiting from out of town. Should I push the issue? Is the burden of proof on me?

If they do say, yes, I have a roommate, then what?

Any advice would be appreciated.

LJ