Buying a rental where the tenant has trashed the place

[Jorge Soto]

Hello BP community. I just wanted to get your opinion/ advise on my current situation. This week I  will be closing on my first investment property. Its a three unit in Sacramento. I will be living in the front unit and managing it myself. One of the unit came with a security deposit that will be transferred to me at escrow. The back unit does not have a security deposit. Just to paint a picture of that unit its needs a lot of cleaning and the dog smell is terrible. My question is can I charge the tenant and security deposit even if the unit is in such terrible condition or should I give him a 30 notice to clean and get rid of that odor before I do my walk through? And if he does not clean up, give him a 30 notice to vacate. The tenants has been there for nine years too.