The regulatory definition of “good cause” to hold a defendant beyond his/her release date pending the filing of an SVP petition is invalid. However, the BPH’s reliance on the regulation is upheld based on good faith. In two consolidated cases the court addressed what showing must be made to postpone the filing of an SVP petition beyond the defendant’s scheduled release date, in order to allow completion of the SVP evaluation. An SVP petition must be filed while a defendant is in lawful custody, i.e., before the defendant’s expected release date or while subject to a statutory 45-day hold. (Welf. & Inst. Code, § 6601.3). The “good cause” required for a 45-day hold is defined by California Code of Regulations, title 15, section 2600.1, subdivision (d) as “some evidence” that the defendant is likely to engage in sexually violent predatory conduct. “That regulation is deficient” because it “links good cause to the wrong showing” the regulation allows good cause to be shown based on the fact that the defendant may be an SVP rather than a justification for the delay in the filing of an SVP petition beyond the defendant’s release date. However, there was no “indication of negligent or intentional wrongdoing by correctional authorities” and the BPH’s reliance on the regulation was “excusable as a good faith mistake of law.” In Sharkey the Court of Appeal’s judgment reversing dismissal of the SVP petition was affirmed; in Lucas, the denial of a habeas corpus petition affirmed. [Note: the companion case was S182355 (People v. Superior Court (Sharkey).]