If there is no written lease, can I evict a tenant?

This is a complex question, and I've had lots of situations involving this. The answer is yes, but you're going to have to establish that there's a landlord / tenant relationship first. In other words, have you been collecting rent from them? If you can prove that there was that relationship, in other words they were paying rent every week, every day, every month, something like that, and establish that you have that, and then you can establish that they stopped paying, then yes, you can evict them. The key is whether or not they were actually a tenant, versus somebody else that you allowed to stay there or all these other things, which might end up being another type of lawsuit that's going to be a lot more involved.