(a) Upon petition of any adult, a judge shall immediately conduct a screening investigation or direct a local mental health professional employed by the department or by a local mental health program that receives money from the department under AS 47.30.520 - 47.30.620 or another mental health professional designated by the judge, to conduct a screening investigation of the person alleged to be mentally ill and, as a result of that condition, alleged to be gravely disabled or to present a likelihood of serious harm to self or others. Within 48 hours after the completion of the screening investigation, a judge may issue an ex parte order orally or in writing, stating that there is probable cause to believe the respondent is mentally ill and that condition causes the respondent to be gravely disabled or to present a likelihood of serious harm to self or others. The court shall provide findings on which the conclusion is based, appoint an attorney to represent the respondent, and may direct that a peace officer take the respondent into custody and deliver the respondent to the nearest appropriate facility for emergency examination or treatment. The ex parte order shall be provided to the respondent and made a part of the respondent's clinical record. The court shall confirm an oral order in writing within 24 hours after it is issued.

(b) The petition required in (a) of this section must allege that the respondent is reasonably believed to present a likelihood of serious harm to self or others or is gravely disabled as a result of mental illness and must specify the factual information on which that belief is based including the names and addresses of all persons known to the petitioner who have knowledge of those facts through personal observation.