a young texas mother, darley rutier, sentenced to death after the brutal stabbing murders of her twoung sons. >> darren believes he's married to an innocent woman. >> when they were telling me that i had done this, i was in shock. i was completely blind-sided. just -- i couldn't even grasp what they were telling me. >> reporter: she's always maintained her innocence. now more than 20 years later, the controversial case is the subject of an abc docu-series "the last defense" from executive producer viola davis that explores whether she should have been put on death row in the first place. >> her conviction is based on problematic evidence. >> reporter: attorneys vanessa podkin and aida lesinring were legal consultants to "the last defense." >> i know she shouldn't have been proven guilty beyond a reasonable doubt. >> reporter: darren rutier is darley's ex-husband and father of her children. >> darley is 100% innocent. the truth is always going to be there. it's still there now. >> reporter: on june 6th, 1996, in a quiet suburb of dallas, texas, 26-year-old darley rutier made a frantic