DCS John du Rose wrote in his 1971 memoir that the murders stopped because his prime suspect committed suicide shortly after the investigation narrowed to three people — implying the killer knew he was about to be identified. Construct the strongest argument that this narrative, however sincerely held by du Rose, functionally serves the same purpose as a false confession: it closes a case without producing evidence, and in doing so, makes the case harder to reopen. What specific features of the 'suicide solution' make it structurally resistant to disproof?