For most of his life Roby Marshall believed his blond, athletic family embodied the all-American dream. His father, Robert, was a prosperous insurance agent; his mother, Maria, was a devoted housewife who fussed over the pancakes she cooked for her husband and three boys. They lived in a rich part of town and ran with the country club crowd that defined the social summit of Toms River, N.J. But on Sept. 7, 1984, their lives shattered when Maria was shot dead in a dark picnic area on the Garden State Parkway. The man who arranged the murder was caught and now sits on death row at Trenton State Prison. As Roby thinks of the condemned prisoner, whose case is being appealed, he feels no pity. No matter that the man is his own father, he says. "I hope he is never set free."

In his bachelor apartment near L.A.'s Venice Beach, Roby, now 24, is strikingly controlled as he speaks of his father's crime: hiring a hit man so that he could collect $1.5 million insurance on his wife to pay off $335,000 in debts and move in with his mistress. Made notorious in author Joe McGinniss's best-selling 1989 account, Blind Faith, the Marshall case is now the subject of a two-part NBC mini-series (see page 11) of the same name, set to air beginning Feb. 11. Although his brothers, Chris, 23, and John, 19, shun any talk of the matter, Roby has sought to expunge his grief and anger by serving as consultant on the show. "I had to come out here and face it," he says. "Then it will be behind us, and it will have been done the right way—like a tribute to my mom instead of some outsiders prying."

Indistinguishable from the California natives with his surfer's tan and tapered swimmer's frame, Roby absently picks at calluses on his palms while describing the nightmare that has haunted him for five years. He was a junior at Villanova University, when Rob Sr. went on trial in January 1986 for his wife's death. As the evidence against their father mounted, all three sons clung desperately to his claims of innocence. But when Rob begged his eldest son to lie to the jury about his whereabouts on the day of Maria's murder, Roby finally renounced all faith in his dad.

Several relatives, he says, "disowned" him for this abandonment. "They think Dad's word is law no matter what. That's bull——. He's a man just like everybody else, and he lies like everybody else." On March 5, 1986, a judge sentenced Rob Marshall to death.

By unspoken agreement, the brothers, who remain close, rarely talk about their father. Still, says Roby, "I can look at their faces and know everything they feel." Chris, now head swim coach at Lehigh University in Bethlehem, Pa., suspected his dad from the beginning and has cut off all contact. John, now studying at Bethlehem's Moravian College, says he still believes his dad and accepts his letters and calls. "John was so young," says Roby. "He wasn't old enough to let it go." Chris and John read the script and gave suggestions but declined any further involvement.

Roby made it a personal mission to ensure the show's accuracy, coaching stars Robert Urich and Joanna Kerns on his parents' mannerisms. "Bob Urich wanted to know what my father drank, how much ice he'd have in his glass," says Roby. "The nitty-gritty stuff that makes it a true story." Executive producer Susan Baerwald says that while Roby was on the set, "he made everybody love him. The outpouring of love from his mother is very evident in his attitude toward life." One of the assistant directors has signed Roby up to continue working in Hollywood with his production team. "It was the only self-serving interest I had in this," says Roby, who majored in communications at Villanova. "To get a good job and a new start." Reliving his ordeal while watching the finished show, he was deeply shaken and promises never to forget one lesson: "Your family, your wife, that's important. Money's not. My father wanted money, he wanted it fast, and to get it, he'd do anything."

As his father's appeal process continues, Roby says that if there is a new trial, "the prosecutor's office wants me to stand up right in front of him and say that he asked me to lie." As his face tightens with resolve against the man whose name he bears, Roby vows, "I'll look him right in the eye and tell him that. I'm not looking forward to it, but if I have to, I will."

—Jeannie Park, Jack Kelley in Los Angeles