Utah Code § 77-9-2

An officer who has made an arrest pursuant to Section 77-9-1 shall without unnecessary delay take the person arrested before a magistrate of the county in which the arrest was made. The magistrate shall conduct a hearing to determine the lawfulness of the arrest. If the magistrate finds the arrest was lawful, the magistrate may commit the person arrested for a reasonable time or may admit the person to bail pending extradition proceedings.