"20/20" - SINS OF THE FATHER - Chris Cuomo Takes Viewers Inside the Powell Family Tragedy, on ABC News' "20/20," Friday, February 10 on ABC

Plus: Growing Up a Mafia Princess - "Mobwives'" Karen Gravano

What would drive a man to set his house on fire, murdering his two sons and killing himself - and could it have all been prevented?  ABC News Anchor Chris Cuomo takes viewers inside the Powell family tragedy with a complete, up-to-date report with exclusive details on the events leading up to Sunday's tragedy, and the fateful decisions by authorities and investigators which preceded the disaster.  Cuomo explores the lingering questions in the case - Did Josh kill his wife, Susan, back in 2009? If so, where is she? And is Josh's father, Steve Powell, the key to the case? "Sins of the Father" airs on "20/20" on Friday, February 10 (10:00-11:00 p.m., ET) on the ABC Television Network.  

Josh Powell has been called a person of interest by police in his wife Susan's disappearance from their Utah home after he and their then 2- and f4-year-old sons went on a midnight camping trip in December 2009. Although never arrested, Josh lost custody of his sons this past September after his father, Steven Powell, was arrested in September and charged with 14 counts of voyeurism and one count of child pornography after pornographic images were found in the home the two men shared with Josh and Susan Powell's boys. Steven Powell denies those charges.

Plus: In the strangely warped world of gangster families, the Gravanos are one of the most notorious - Sammy "The Bull" Gravano, John Gotti's former right hand man, is the legendary hit man turned highest ranking mobster to ever turn informant. Now his daughter, Karen Gravano, a cast member of the hit show "Mobwives," has written a new book, Mobdaughter, about her life growing up Gravano. Karen takes ABC News Correspondent Jay Schadler back to the New York neighborhoods where she grew up treated like a "Mafia Princess." She speaks candidly about being the daughter of a man who pulled the trigger or arranged the murder of at least 19 people.

David Sloan is executive producer of "20/20".