jim ever really got distant. if anything, i think their, you know, relationship just grew stronger and stronger. >> reporter: it's a foggy night in houston in 2012. and sandra melgar is feeling pretty good on this night, so she and her husband jim decide to go out for a celebratory dinner. it's their 32nd anniversary. >> what she's told me was that they were gonna go out to dinner. they were going to their favorite mexican place that they go almost every weekend. and they stopped by a local cvs just to grab some drink mixers on their way back home. they got home. they started getting drinks ready. they got into the jacuzzi in their bathroom. they spent a few hours in there. just this and that, chit-chat. >> suddenly, the melgars' four dogs started barking in the backyard. so jim got out of the tub to bring the pups inside. sandy continued to soak. the jets roaring, as the water massaged her for about 5 to 15 minutes. >> i think he took a few minutes, so she decided to get out of the jacuzzi. she went to her closet, sat on her chair that she has in her closet, and started putting lotion on. >> reporter: that's the last thing that sandy says she remembers that night

jim. >> i remember her being like, "oh, your uncle. oh." >> reporter: the melgars' life revolved around not just family, but church, too. they'd joined the jehovah's witnesses early in their relationship, but by her early 20s, daughter lizz had left the church. newly independent, she rushed into a marriage. a bad one. >> true that he was involved in heavy drugs? >> yes. >> that was the end of it? >> that was it. i didn't want to live that kind of life. >> reporter: but her parents' marriage just kept going through sickness and health. in fact, in recent years, jaime was looking younger than ever on a vegetarian diet and exercise regimen. >> he realized he was getting older and he just wanted to make sure he was in the best physical shape. >> your mom. your poor -- >> mom. meanwhile had a constellation of health problems, didn't she? >> yes. >> lupus? chemotherapy involved in that? >> at times, yeah. she also had epilepsy. >> did she have the seizures? did you ever see her -- >> yes. yeah, she did. >> reporter: then december 2012 rolled around. their 32nd wedding an