>> reporter: and frances might have forgiven bill yet again but this time, bill's mistress, bonnie contreraso. during their three-year affair, bill had paid her rent and even bought her two cars, a bmw and a mercedes. >> bonnie contreras would take compromising photos, kind of just gather all these nuggets, that if things ever went south, she had all the proof she needed to kind of force you to do what she wanted. >> my mother was on the verge of a nervous breakdown because bonnie was taunting her constantly. >> she's texting and calling frances. bonnie would call her every explicit name in the book. >> reporter: it was a toxic love triangle destined to explode and it did. frances hall was stopped at a light on this road outside of san antonio when she saw her husband, bill, atop his harley davidson, followed closely by bonnie driving the hall family car. >> i get a phone call from my mom, and she said, "i just saw your dad, and i just saw bonnie. i'm turning around. i'm gonna confront her." >> reporter: frances was revved up and driving her own cadillac escalade. she hit the gas and began p