Government and its agents, (bureaucrats, prosecutors, judges, officers, agents, etc), must respect the rights of citizens and non-citizens alike as guaranteed in the Constitution. 

Government workers have a huge amount of power and can destroy someone's life.  This ranges from allegations of a CPS worker based on hearsay to a lazy cop who just wants to harass y ou.  Your only protection is the law and advocates, such as attorneys, who know the law and how to protect you. 

Remember, refuse all tests.  Politely assert your right to remain silent and ALWAYS ask for an attorney to be present.  Government Agents (cops, cps workers, investigators) will always try to be nice and talk to you, or do the "bad cop" routine and try to scare you into talking.  They are trained to do this.  Remain silent.  Don't consent to any search.  If they want to ruin your life, make them work for it.  Government is not your friend when they slap those handcuffs on you and take away your freedom..........