Legal Question in Real Estate Law in California

I assume you mean it is worth $10,000.00. By closed do you mean the shop closed for the day or that the business shut down?

If keeping your tools at the business was normal, tell the owner he needs to make a claim on his property insurance coverage, especially if you are an employee instead of an independent contractor. If you had his permission to keep your tools there and you did not put them in a place readily accessible to the public then he may very well have had a duty to you as to the safety of the tools. If he tells you his insurance will not pay demand to have the contact information to speak to his insurance adjuster to find out why they deny liability.