>> and then, you're, what, goin' back to school and -- >> yep. exactly. >> reporter: still it was hard for the family to put trish's death behind them. and something else was troubling. emily and sara had a fuzzy recollection that trish wasn't the first person in the family commune to die. they'd recently met a teenager who'd also once been on the fringes of the commune. and he told a story with painful echoes. coming up, a tale of tragedy and mystery. >> i knew something wasn't right and he told me, your mom and sister have been missing. >> two members of the commune vanish in thin air. when "dateline" continues. and the 12-hour pain relieving strength of aleve. so...magic mornings happen. there's a better choice. aleve pm.