Legal Question in Business Law in California

You cannot cross-complain for malicious prosecution. You have to win the first action and thereby establish that it was meritless before you can sue.

Your post suggests that you are thinking of doing a cross-complaint. You may indeed have some ground or basis for cross-complaining against this landlord; however, it wouldn't and couldn't be for malicious prosecution or the related tort, abuse of process.

I assume you have been sued, even though you don't say so specifically. Your primary focus should then be on making a strong defense to the landlord's suit. You tell us nothing, however, about the substance of the suit. Is it an unlawful detainer? If so, bear in mind the accelerated time line for getting your response on file.

A response to the suit, probably an answer, could be accompanied by a cross-complaint for any causes of action you may have against the landlord. An action for malicious prosecution or abuse of process must, however, await the (favorable to you) outcome of the present suit. Please feel free to contact me directly if you'd like further review.