How will they prove that if the parents say the son also refused to tell them anything about the missing girlfriend?
Unless the son confessed to his parents via email, the state has no evidence of complicity.
“How will they prove that if the parents say the son also refused to tell them anything about the missing girlfriend?”
In the absence of any other evidence, they won’t. Just because they can’t prove it in court, I can still evaluate the facts as presented. So far, they appear guilty to me. Could they reasonably assumed anything else when he showed up without his girl, in her car, lawyered up, hid the car in the garage and wouldn’t talk to the police? Not in my opinion.