A warrant issued pursuant to section 1a shall recite the substance of the accusation contained in the complaint. Except as permitted in section 1c of this chapter, the warrant shall be directed to a peace officer; shall command the peace officer immediately to arrest the person accused and to take that person, without unnecessary delay, before a magistrate of the judicial district in which the offense is charged to have been committed, to be dealt with according to law; and shall direct that the warrant, with a proper return noted on the warrant, be delivered to the magistrate before whom the arrested person is to be taken. The warrant may also require the peace officer to summon the witnesses named in the warrant.