Legal Question in Construction Law in California

Was the contract for a specified piece of work, or for a specified duration of time? Most construction contracts are the former; they may specify that the work is to be completed within a certain time, but what the client is paying for is completion of a job, not putting in a certain amount of time.

The builder's response -- involving the police, etc. -- seems peculiar. He is either responding irrationally and unprofessionally, or there are some important facts missing from your question. An underpaid contractor doesn't have cause to call the cops -- his recourse is to get a lawyer and file a civil suit. The police ordinarily would tell him that when first contacted.

Finally, I'm uncertain why you ask if the contract is still "valid." When an initially valid contract is breached, it remains valid. However, the duties of the non-breaching party may be suspended or terminated as a result of the breach. In other words, if your contractor stops working, your contractual duty to pay him may be suspended or terminated; and, on the other hand, if you don't pay your contractor according to the contract terms, he may be excused from performing any further services for you until paid, or perhaps ever. I think we need full details to give you a useful response.