Any behaviour can be rationalized!
My love for my children is unconditional. I would have to let them know that there are consequences for their actions. I would do this in love and not judge them. If they were in legal trouble... Well this would be left up to the individual. But in no circumstance would I enable them and if they were using drugs or involved in criminal activity would they be welcome in my home. Sounds like tough love but as a parent sometimes we have to draw boundaries with our own children which is painful and sucks. I hope this helps. One more thing about this... Trust between a child and a parent begins when they are very young and never stops... It is not the child's responsibility to build this it is the parents...
If my child had committed a crime knowingly, I would urge him or her to turn himself or herself in, and try to ensure that they had a good attorney so that the trial would be fair. If I felt he or she had been falsely accused, I would do everything possible to see that the result was an acquittal.
That would depend on the circumstances, I had two cousins drafted for Vietnam, the older one went, came back and told of the atrocious mess it was, his younger brother got his draft notice and my aunt helped him get to Canada, was she wrong, I don't think so.
I'd help protect them, if it were danger. If they committed or were accused of a crime, i'd help them find a good lawyer. My actions would depend on the circumstances, but generally speaking, I'd do what ab ethically and morally principled person should, after considering relevant factors.
Hire a good lawyer. I'm assuming on the run from the law. I am not so naieve as to think the police and justice system actually works as they should.
Get the story and age of child-if underage call social services and report abuse/neglect.
It depends on the severity of the 'crime' and if there actually was one.
My daughter could be running from an abusive relationship. Whatever it is, I will give them refugee status. If 'the law' is after them, I would try to talk them into giving themselves up and dealing with their actions. But I'd always do as much as I could to help them.
I would turn them in and hope that justice is served. Whatever that looks like.