(a) It is the public policy of this State to protect the public from crime and violence by encouraging all persons who are witnesses to crimes, or who otherwise can give evidence in a criminal investigation, to cooperate with the criminal justice system and not to penalize these persons for cooperating with the criminal justice system.
(b) If an individual is a witness to a crime or can otherwise give evidence in a criminal investigation, a law-enforcement officer may not detain the individual exclusively for any actual or suspected immigration violation or turn the individual over to federal immigration authorities absent a judicial warrant or a valid court order.