>> had they told you at this point what was going on? >> they hadn't, and i just kinda' picked up what was going on through conversation. >> but heather -- >> was nowhere to be found. no one could get ahold of her, which to me was very surreal because you never think something like that can happen until it does. it's something you see on "dateline" specials. it's not something you see in real life, so your brain almost tells you it's not happening. >> reporter: that's when it dawned on them, they could retrace heather's steps by way of her cell phone. she was still on their family plan. >> ended up going online and going to our cell phone provider, 'cause you can look at the call records. and they pull up the information and they e-mailed it to us. >> reporter: they could see the most recent calls their daughter made and received. after her call to bri, heather dialed another number several