Legal Question in Civil Litigation in California

A civil action may be a better way to go.

You can complain to the local District Attorney, but there's no guarantee that they will do anything. The D.A. has limited resources and therefore can't prosecute everything that warrants it. Don't be too shocked if this is a case they don't want to pursue. Unless the harrassment you describe is serious enough to warrant prosecution, there seems to be nothing really outrageous going on.

One reason the D.A. might not be willing to do anything is that you have an effective remedy available in the form of a civil suit. You say that you already have a civil suit pending against this woman, so I assume you already have a lawyer. I don't understand why you are asking for advice from us instead of from your own counsel.

As always, more facts would make this an easier question to answer. You say she is trying keep you away from her child -- well, why is staying away a problem? Does the child live with your fiance? If the child lives with the mother, does she object to you being with your fiance when he spends time with the child? Is this part of a custody battle between your fiance and his ex?

Your civil suit may have some serious problems, which I assume you will have discussed with your counsel. For one, defamation cannot be based upon statements made in the course of litigation (e.g. in court or in court papers and, in many instances, in deposition testimony) because such statements are "privileged" -- e.g., immune from the type of liability you want to impose. Statements she has made outside of court MAY be actionable, but only if they are false and were directed to an audience (even if it was only one person, including your fiance or his child) who found it credible. If she's just bad-mouthing you to your fiance, he probably doesn't believe it and you won't get very far in a lawsuit.

You say the ex is "attempting" to get a restraining order against you. If this effort is still underway, your best strategy is probably to defend yourself in that context before you worry about suing her. While you say you want to sue her for "abusive process" (it's actually "abuse of process", but this is a common mistake), but such a suit will not lie unless you can show that the underlying case was resolved in your favor. In other words, if the proceedings to get a restraining order are underway, it's too early to sue, and if the ex wins, then you will have a very hard time prevailing on an abuse of process theory. This is one reason (among many) why your first concern should be defending yourself in her action.

As I said, though, your best source of information and advice is your present attorney. If you don't already have one, get one right away.