heather collins: it says it's a young female. so i immediately start looking for the younger two because they're in high school in newburgh. you just want to make sure. yeah, you just want to find your kids. andrea canning: i just want to find her. just as a mom, i just want to make sure everybody's safe. yeah, i just want to find my kids. andrea canning (voiceover): heather found her two youngest. they were ok. but halee wasn't answering her phone. and friends told heather she didn't show up to take her exam at the university. it's not like her to miss class, not like her to have her phone turned off. andrea canning (voiceover): not like halee rathgeber to go missing. coming up, what had happened to halee? andrea canning: are you getting a sick feeling? oh, i was sick all morning. it was so much anxiety. and i just started screaming her name. like, my stomach had dropped, and i was like, oh, my god, where is halee? andrea canning (voiceover): when "dateline" continues. upset stomach iberogast indigestion iberogast bloating ibero