CA credit card fraud law, what action can I take against person that used my credit card checks without authority

Report this to protect yourself.

Fraud is actionable if certain elements of proof are established by the evidence. Using the written documentation you have is a good place to begin. Contact a local lawyer - many may give you a free consultation for an hour - to discuss your specifics. Discuss the matter with your attorney under the protections of attorney client privilege before you do anything else. Far too many variables exist in the short post you wrote for any further observation by me.

Good luck to you.

NOTE: This answer is made available by the lawyer for educational purposes only. By using or participating in this site you understand that there is no attorney client privilege between you and the attorney responding. This site should not be used as a substitute for competent legal advice from a licensed professional attorney with whom you have established an attorney client relationship and all the privileges that relationship provides. The law changes frequently and varies from jurisdiction to jurisdiction. The information and materials provided are general in nature, and may not apply to a specific factual or legal circumstance described in the question

I am not licensed in California. You need to report the unauthorized use of the checks immediately to the police and Capital One. You should also notify the credit bureaus of this activity and check your credit reports in case there is other fraud committed by the same or persons. Be sure you have provided change of address information to all your other creditors.