I'm Doug, and I'm very sorry to hear of your situation. My goal is to provide you with excellent service today. I've been a CA licensed attorney for 30+ years, and I handle employment law, as well as tort law. I would add that I handled construction law cases for many years.
This seems like a very crucial matter for you, and your questions and issues suggest that an in-depth conversation might best suit your needs. If you are interested, for a nominal charge I can offer you a private phone conference as opposed to continuing in this question and answer thread which is searchable and viewable by the public.
Let me know if you don't want a call and I will be happy to reply to you in this question thread format.
Either way, whether I call you or not, in order to give you a clear and concise answer, I will need some additional information about the circumstances, please. Please understand that asking "please advise" is not a useful question for a lawyer. I need many more facts than you have provided.
1. How long did this guy work for you?
2. Are you saying that he deliberately contacted your customers in an attempt to steal them from you?
3. Was this person an employee or an independent contractor---based on your designation of him?
4. What did he call your comp carrier for?
5. What did he contact the IRS for?
6. You wrote: He has done everything to cause harm to my business Please explain in detail as this is critical to your case and I can't know what you don't tell me.
The above questions are only the beginning, if you need a helpful answer.
Thanks in advance,