Tenants Barking Dog?

[Chris Heeren]

I have a tenant who just signed on a month ago (in a Duplex) and has a small dog that barks all day long. My other tenant has been complaining that this dog constantly barks and keeps him up during the day as he works 3rd shift. He plans on calling the police if the dog doesn't stop. Both tenants have small dogs and both agreed to pay the extra security deposit and monthly rent increase for having pets. What exactly should/can I do in this scenario?