Imprisoned financial scam artist Bernard Madoff boasted in a jailhouse letter that he is quite the celebrity and treated like a Mafia don, ABC News said on Thursday.

ABC, which will feature an interview with Madoff's daughter-in-law on news program 20/20 on Friday, released portions of a letter provided by Stephanie Madoff Mack, whose husband committed suicide in the wake of his father's conviction in a massive Wall Street fraud.

Mack told ABC she had written Madoff a letter detailing family events he was missing due to his life sentence of 150 years behind bars, as a way of rubbing salt in the wound.

I thought that that would really sting him, Mack said, adding that her plan backfired.

The smug-sounding reply from Madoff, whom Mack said she holds responsible for her husband's death, enraged her.

As you can imagine, I am quite the celebrity, and am treated like a Mafia don, Madoff wrote from the North Carolina prison where he is incarcerated.

They call me either Uncle Bernie or Mr. Madoff. I can't walk anywhere without someone shouting their greetings and encouragement, to keep my spirit up.

It's really quite sweet, how concerned everyone is about my well being, including the staff ... It's much safer here than walking the streets of New York.

Mack described her reaction as having been sick to my stomach, but said she didn't think she ever showed the letter to Madoff's son, Mark.

My husband was in terrible, terrible pain, she said. He was so deeply hurt by it all, that he just, he, he just couldn't move past it.

Mark Madoff committed suicide in December, two years to the day after Madoff's arrest in the more-than $50 billion swindle, the biggest Ponzi scheme in U.S. history.

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.

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