There have been intensive investigations, but still people refuse to believe the results. Henri Paul's family said the medical findings had been tampered with.
I remember the case of James Hanratty who was hanged for murder in the 1950/60s . His family insisted he was innocent , his landlady gave him an alibi , and they said the girl he raped and shot who identified him was lying.(her lover was murdered). When DNA tests were applied to their clothes years after his execution it proved he was there, he had raped and he had murdered. The landlady admitted she had 'made a mistake' about the date, but the family insisted the samples had been tampered with.