Not being honest about pets

[William Rich]

Hello all-  Does anyone have any suggestions on what to do when a tenant is keeping more pets than they agreed to in the contract. My tenant is supposed to have one cat which they pay extra for. My tenant is well aware that there is a charge per pet.  I've seen two cats in the window of the apartment on two separate occasions and the downstairs tenant has seen the cats as well.  I questioned my tenant about the second cat but they have denied it.  Any suggestions?