sandi johnson's family and friends would agree. the young mom was petite, pretty, and devoted to her two kids. but when she went missing, police wondered if sandi's home life was as happy as it seemed. they quickly uncovered a web of romantic relationships and a dark mystery that would take years to solve. here's andrea canning with "the disappearance of sandi johnson." >> it's a celebration no mother would ever want to miss. a child's 5th birthday. but suddenly, she was gone. out of his life. >> there's nothing that anybody could really do to fix that or repair that missing part. >> his mother, sandi johnson, was outgoing, energetic, and an awesome mom. >> those kids were everything to her. >> so, why wasn't she there to sing happy birthday to her son. >> all they knew was that she just disappeared into thin air. >> she should have seen you get married. she should have seen you go into the military and become a police officer one day. >> it's the toughest thing i've ever had to deal with. >> it was heartbreaking and baffling. >> it

sandy hook elementary school shooting. she is a licensed marriage and family therapist. halls shan nay johnsonwas murdered in new york while she was two months pregnant with her now 18-year-old son. in 2010, her 17-year-old son kendrick was murdered in queens, new york, weeks before his high school graduation. she is now a volunteer with moms demand action and founder of the kendrick murrow junior foundation. laid, thank you for coming and having this incredibly tough conversation with me. i want to gen with you, the funerals for the uvalde children and the two teachers, the funerals begin today, two of them. your family and marriage counselor therapist. you must be through this before. what do these families need from us right now? >> i would think to give them space to give them space to give them time to follow their lead to not push them to make statements or decisions that, you know, are in perhaps other people's best interests but maybe not their own, follow their space. respect their space. follow their lead. give them time. >> you know, i really wanted to talk to you, you are an incred