18150. (a) (1) An immediate family member, an employer, a coworker, an employee of a secondary or postsecondary school that the person has attended in the last six months, or a law enforcement officer may file a petition requesting that the court issue an ex parte gun violence restraining order enjoining the subject of the petition from having in his or her custody or control, owning, purchasing, possessing, or receiving a firearm or ammunition.

(2) For purposes of this subdivision, “immediate family member” has the same meaning as in paragraph (3) of subdivision (b) of Section 422.4.

(3) This chapter does not require a person described in paragraph (1) to seek a gun violence restraining order.

(b) A court may issue an ex parte gun violence restraining order if the petition, supported by an affidavit made in writing and signed by the petitioner under oath, or an oral statement taken pursuant to subdivision (a) of Section 18155, and any additional information provided to the court shows that there is a substantial likelihood that both of the following are true:

(1) The subject of the petition poses a significant danger, in the near future, of causing personal injury to himself, herself, or another by having in his or her custody or control, owning, purchasing, possessing, or receiving a firearm as determined by considering the factors listed in Section 18155.

(2) An ex parte gun violence restraining order is necessary to prevent personal injury to the subject of the petition or another because less restrictive alternatives either have been tried and found to be ineffective, or are inadequate or inappropriate for the circumstances of the subject of the petition.

(c) An affidavit supporting a petition for the issuance of an ex parte gun violence restraining order shall set forth the facts tending to establish the grounds of the petition, or the reason for believing that they exist.

(d) An ex parte order under this chapter shall be issued or denied on the same day that the petition is submitted to the court, unless the petition is filed too late in the day to permit effective review, in which case the order shall be issued or denied on the next day of judicial business in sufficient time for the order to be filed that day with the clerk of the court.