I have actually thought about this for an unusual amount of time in the past, as I have been the victim of crime and watched the perpetrator sit in court across from me flanked by his parents - one on either side. That hurt me more than anything he had done.
I would not publicly support my child if it caused further upset to a victim.
However, as I said, I have thought about why, why, why, why did they support him? It's simple. They love him. If my child was involved in criminality, you don't just stop loving them? You can't! They're your baby!
After a lot of soul searching, I'm no longer angry at them. I'm no longer even angry at him. It's no longer a part of my life.
I would support your child in private, no matter what. I don't think that people are pure evil. I would not support someone if it meant causing further injury to the victim though. I would draw the line there and tell my child why.
I am not God. It's not my job or role to judge. I don't judge you for supporting your child. You carried them in the womb, you gave birth to them, you reared them. You don't manage to turn that off. I don't know what crime was committed or what went wrong along the line somewhere, but crime isn't usually committed out of the blue.
I know your heart must be broken. I would continue to support your child through prison presumably? I'm presuming that you are the mother and not the father.
At the end of the day, the only one who can judge, is God. Not one of us is without sin.