Miriam Helmick was sentenced to life without parole for the murder of her second husband, Colorado businessman Alan Helmick.

I know that I didn't kill him. Helmick spoke with ABC News' John Quiñones in a prison interview for a new 20/20 airing Friday, January 31, at 9 p.m. ET on ABC, and streaming the next day on Hulu.

It doesn’t take much for longtime ABC News correspondent and host John Quiñones to captivate an audience with stories of his life and career. That’s exactly what happened when Quiñones visited the AL ...