and craig didn't seem to care who knew that things were toxic inside the heidt family. . >> he said that they did not get along. that he was a back sheep of the family. and he wouldn't help them if they were on fire. >> craig said that he said the same sentiment to her. >> craig said that if his father was on fire, he would not urinate on his father to put him out. >> father and son, brother and brother, a husband and wife all square it up in the court. the story being told in the court was of the heidt family destroying itself. a match had been lit, as the prosecutor told him. and come late august, an explosion was about to go off. robbyn told the jurors about a driveway altercation a week or two before the shooting. between her and her father in law. an argument that became physical. >> philip said, you know, look around you. these are things that craig cannot give you. these are things that only carey can give you. and he said you don't understand how craig is. he has issues that you don't understand. and that upset me. i said, i'm leaving. i'm getting in the car and

craig heidt. coming up. >> craig.with me throughout this whole investigation? >> yes sir. >> about everything? >> yes sir. >> what was the secret that craig heidt was guarding so secretly? as shattering surprise was in store for folks in emington county. >> robin said she was having sex with you? >> when dateline continues. ew tequila lime shrimp. that's seven endless choices for just $20. right now, only at red lobster. welcome to fun dining. [music playing] subject 1: cancer is a long journey. it's overwhelming, but you just have to put your mind to it and fight. subject 2: it doesn't feel good because you can't play outside with other children. subject 3: as a parent, it is your job to protect your family. but here is something that i cannot do. i cannot fix this. i don't know if my daughter is going to be able to walk. i don't know if she's going to make it till tomorrow. [music playing] interviewer: you can join the battle to save lives by supporting st. jude children's research hospital. families never receive a