Jason killed Nicholas. No question.

No question? There are no witnesses, no physical evidence, no proven confession (unless you take Frederic Bourdin's word as gospel) and no body. So to say there is "no question" about a case that has no proof and so much mystery hanging over it is completely untrue.

There is some evidence that Jason might have, but no proof. Its possible that a stranger kidnapped and killed Nicholas. It's possible that Nicholas ran away and was kidnapped or murdered, as many runaways are. It's even possible that Nicholas is still alive and being held captive like Colleen Stan or Ariel Castro's victim.

I can see why people think that being killed by Jason is the most likely cause of Nicholas' death, but nobody can claim to know this.