Who fits the model of "stupidity" more than the van Dams and their friends? You are right that "Abduction/Murder is not a rational act", and this sad group had demonstrated a surprising obsession/compulsion with personal vanity and self-indulgence, leading to the demise of a child.
Perpetrators are often very conflicted in their behavior and sometimes want to be stopped.
If this is the case with DW, then he would have confessed to the crime long ago. No, DW has no choice but to accept the fact he was in the wrong place and the wrong time and has to fight a false accusation.