decades after archie mcfarland was murdered, the case against janos kulcsar finally came to court. and, of course, the prosecution's star witness was mary ann mcfarland. what did she know, and what would she admit? could her testimony sink her lover or maybe save him? coming up -- tough questions -- >> let me make it very simple. are you in love with him? >> and raw emotions. >> i'm so sorry. i'm so sorry, son. and she went hysterical. she lost it. >> when "dateline" continues. any who invented car vending machines and buying a car 100% online. now we've created a brand-new way for you to sell your car. whether it's a year old or a few years old. we wanna buy your car. so go to carvana and enter your license plate answer a few questions.