nermeen: i want to turn to walter lee irvin's sister henrietta irvin. here she explains walter's account of what happened the night he and sam shepherd were shot by sheriff willis mccall and a deputy. >> when he opened the door for sam and sam turned to get out of the car, they shot him right in the forehead. just like that. fast and hem so felt his way to moving, until he knew that sam was dead. by that time, he at shot him also. and he said he remembered hearing him say, come on back, i've killed the son of a bit ches. he said when mr. yates got back and he was shining his light on him, he kicked sam and shine the isght on him and said this -- not dead. nermeen: gilbert, your response to what she said? >> this is a seminal moment in this entire story. basically, the equivalent of cell phone camera footage of a killing. sam shepard and walter irvin are handcuffed together. mccall comes around and shoots sam shepard three times. he dies instantly. walter irvin is shot twice. he cannot run because he is handcuffed to his best friend. he lays on the ground