i did not kill bob mcclancy i had nothing to do with killing bob mcclancy.d of a drug overdose. >> and that was martha ann's story, every ward of it was true, she swore. >> if martha ann believes her husband was murdered, she would stay it wished chuck kaczmarczyk. he was there with bob mcclancy when he died. he was the one who took photographs of mr. mcclancy, and manipulated the crime of the death weather was a crime scene or not. >> but, battle of the corn artist was just getting started. and the prosecutors believed they had a strong case. >> what was the most important piece of evidence in your view? >> the most important piece of evidence, of course, was the confession taken from chuck kaczmarczyk. and what a darkened ev a story of murder chuck was about to tell. >> coming up, >> he had said we will make it look as natural as possible. >> powerful testimony from the star witness, and from a reluctant son. >> she looked at me as if she wished i was dead. >> when dateline continues. just look around. this digital age we're living in, it's pretty unbeliev