paul's friend, steve whitley. >> everybody was in such shock that i don't think the reason mattered.are of our friend. >> reporter: how was paul? >> grief-stricken. >> reporter: so was linda's family. her niece, ricki, remembers how paul changed the funeral arrangements to help them deal with linda's sudden death. >> he allowed the casket to be open so my mom could see her sister, wrap her mind around her sister being gone. >> reporter: linda was now only a memory. but she'd left behind a perplexing medical mystery. what caused the mysterious illness that took her life? what were her symptoms? >> diarrhea, vomiting, dizziness, fatigue. >> reporter: and it wouldn't go away? >> and it wouldn't go away. >> reporter: after linda's death, they discovered a medical chronology on her computer at work. she'd kept careful notes about her symptoms from the very beginning. it went back a year, to june 28th, 1993. she wrote, "felt fine all day, worked late, had a salad for dinner, woke up in the middle of the night vomiting." a month later, july 24th, 1993, "approximately one hour after eating i