​I have to terminate an employee for sexual harassment tomorrow

Do I need to do anything special for this?

I know the correct answer is: speak with a lawyer. But I can’t do that until next week and he and the woman he is harassing are working alone tomorrow night.

He has repeatedly made advances towards her, despite her telling him the attention is unwelcome. He has done this at work and off work. He has made comment about her sex life with her boyfriend. He’s brought up his penis size multiple times. There are a few other things that are not sexual in nature but are highly inappropriate.

I was made aware of this today, but the harassment has been happening for more than a month. The employee has spoken with a coworker about this several times over the last month and the coworker wrote down dates and what was said as best they could recall. The coworker also has her own instances of inappropriate behavior, albeit slightly less serious.

My plan is to have a witness, send the woman out for a coffee so she’s not in the building when I’m firing him, and to tell him two of his coworkers have made complaints of inappropriate behaviors. I plan to give the examples I listed above and ask him if he said those things. Then I will tell him I can no longer employee him and be done with it.

Any thoughts? We are a small operation, two owners and 5 employees. I’ve never had anything like this before and I don’t want to make any mistakes.

Edit: this is in Arizona