48 HOURS: PRESUMED GUILTY to Air 11/24 on CBS

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Frank O'Connell vowed he'd always be there for his son, Nick. Keeping the vow was tough, because in 1985, O'Connell was convicted for killing a man in Pasadena, Calif. Frank O'Connell swears he was innocent.

"You watch TV and you say, 'That doesn't happen.' Well, it does happen," O'Connell says on 48 HOURS: "Presumed Guilty," to be broadcast Nov. 24, 2012 (10:00 PM ET/PT) on the CBS Television Network. "It happened to me, it can happen to anybody."

"He's been in prison since I was 4," Nick O'Connell tells 48 HOURS Correspondent TRoy Roberts. "He was convicted of first-degree murder and he maintained his innocence since day one."

Frank O'Connell was a former high school football star and local hero who had lost his way when was convicted of killing Jay French, the ex-husband of a woman he had dated for a short time months before. French was shot dead outside of his Pasadena home. French and his ex-wife, Jeanne, had a bitter custody dispute over their son. Police maintained O'Connell shot French to help Jeanne. O'Connell said he was 30 miles away and had witnesses to prove it. On his attorney's advice, O'Connell waived his right to a jury trial and put his fate in the hands of a judge. He gambled wrong and was sentenced to 25 years-to-life in prison.

Nick never gave up on the father he never really knew. When he was 15, he began digging through files of his father's conviction. "For my own security, I need to know whether my father did this or not," Nick says.

"Everyone says they're innocent when they're in prison," Jolene Cordova, Jay French's sister, tells 48 HOURS. "My brother was murdered just like he meant nothing, shot down like an animal. I think Frank O'Connell shot my brother."

TRoy Roberts and the 48 HOURS team piece together the emotional and powerful story of a loving son and his imprisoned dad through interviews with Nick and Frank, Jay French's sister, police investigators, a key witness and others. Roberts also talks to Kate Germond, the director of Centurion Ministries, an organization that investigates claims of wrongful convictions. Centurion took on O'Connell's case 13 years after he entered prison.

"Presumed Guilty" was produced by Judy Rybak. Doug Longhini is the investigative producer. Lauren Clark is the field producer. Al Briganti is the executive editor. Susan Zirinsky is the senior executive producer.

"Presumed Guilty" is part of 48 HOURS' 25th full season. It is the third-longest running primetime series and has been the #1 non-sports program on Saturday nights for six consecutive seasons.