My elderly mother loaned a friend $10,000. To pay back the loan, the friend wrote a number of checks to my mother and post dated them for the first day of the month for each month for my mother to cash. The check amounts were $500 each. The first 2 checks came back not sufficient funds. After some of the others were deposited, they all came back "closed account." My mother has a hand written note written by the check writer stating she promises to pay my mother back. The "friend" no longer accepts my mother's phone calls. I took my mother to the local sheriff's department who stated my mother will have to sue the friend in Civil Court. In efforts to write a demand letter, I would like to include the California bad check law, but cannot locate it. Can you help me? Thank you.