A curious neighbor. It was scary. The look on his face was almost undescribable. What had she seen . Was this drowning really an accident . Shes got a huge gash on her head. Something like that is not consistent with just falling down. A husband and father is suddenly under suspicion. Hes crying and were crying. He said, they think i hurt mom. Three daughters stand by their dad. And one prosecutor stands firm. Hes holding his wife of almost three decades under the water. My job is to get justice for cristi hall. Was it murder . Hello and welcome to dateline extra. A young woman peers into her neighbors yard and sees something for a few seconds. A man, a woman, and a moment thats unsettling. What she saw and what she did would set in motion a chain of events that would divide a family and a jury. Here is keith morrison. We know the truth. And we know everything that happened. How do we know what we know . Its emotionally unsatisfying not to have that answer. Though it is, even if weve s