If she saw her father-in-law, who is serving a 150-year prison sentence, Mack told “20/20” reporter Chris Cuomo: “I’d spit in his face.”Mark Madoff committed suicide last December, exactly two years to the day after his father was arrested for orchestrating the biggest Ponzi scheme in U.S. history.In the interview Mack also revealed a jailhouse letter she had received from Madoff after his son’s death. The network will release more segments of the interview on its Web site on Thursday.The interview will air on “20/20” on Friday. Mack, whose autobiography “The End of Normal: A Wife’s Anguish, A Widow’s New Life” will be published on October 20, will also appear on “Good Morning America” next week.