What are the landlords rights

What are the landlord’s rights? Unfortunately the landlords don’t have that many rights and depending in the state you’re in the laws is different but there are usually all about the tenant. My father was the owner of some apartment couple years ago, one of the tenants that were there didn’t pay rent for about eight months because they knew how to beat the system and free lode. The first couple of months when by and the tenants were not making their monthly payment so my father when and got an eviction notice, the tenants had a couple of days to move out instead of moving out the tenant when to court and put a complaint against my father saying that the reason that they didn’t pay their rent was because there was insects in the apartment which it wasn’t true. It is against the law to have an apartment in that type of conditions so he got away with it. My father had to pay to have the apartment spayed down while the tenant got away from paying any rent, they did this the hole time they were there. Mean while my father would show up to the apartment to see if he could get paid and couple of the times that he when the tenants were doing drugs so my father called the cops to let them know that not only they won’t paying rent but they were doing drugs in the apartment. Little did my father knew that the cops couldn’t do anything about it they just advice him to take them to court. For the entire eight months my father had to go to court on an off and he did not get not one monthly payment. I think it’s so unfair that how there are people that know how to beat the system and the law allows this and they could go months with not paying anything.