Bernard Madoff's daughter-in-law, whose husband committed suicide in the wake of his father's exposure in a massive Wall Street fraud, holds Madoff responsible for her spouse's death and said that if she saw him today, she would spit in his face.

Stephanie Madoff Mack, the first member of the family to speak publicly about the $50 billion swindle and its repercussions, told the ABC News show 20/20 I hold him (Madoff) fully responsible for killing my husband.

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.