Oregon Revised Statutes Human Services; Juvenile Code; Corrections § 419C.080

(1) A peace officer, or any other person authorized by the juvenile court of the county in which the youth is found, may take a youth into custody in the following circumstances:

(2) In any order issued under subsection (1)(b) of this section that may result in a substitute care placement or detention, the court shall include a written finding describing why it is in the best interests of the youth to be taken into custody.

(3) A peace officer or person authorized by the juvenile court shall take a youth into custody if the peace officer or person authorized by the juvenile court has probable cause to believe that the youth, while in or on a public building or court facility within the last 120 days, possessed a firearm or destructive device in violation of ORS 166.250, 166.370 or 166.382.