dr. mary ellen o'toole saying this is a complicated case with multiple motives spelling disaster. together that made this a very lethal pair. >> a very preliminary determination of the cause of death is stabbing. >> reporter: for nicole's mother, it's too much to bear. >> her favorite color was blue. nicole was a very loveable nicole touched many people throughout her short life. i can't do that part. >> reporter: while authorities wait for the results of an autopsy they have concluded that nicole was using a messaging app called kick to communicate with eisenhower, raising questions about possibly dangerous encounters. >> i'm willing to say kick is a devil for young children. it's like a free ability to text. anything you want. parents can't see the phone numbers that are coming in and out. >> reporter: experts say many of these anonymous apps are popular with teens and predators. >> you can sign up as anybody you want to be. hunting preserve for some of these pedophiles. >> reporter: here's how kik works. download the app for free, add any name and any photo, send messages, phot

dr. mary ellen o'toole psaying this is a complicated pcase with multiple motives pspelling disaster. p>> there's synergy that came ptogether that made this a very plethal pair. p>> a very preliminary pdetermination of the cause of pdeath is stabbing. p>> reporter: for nicole's pmother, it's too much to bear. p>> her favorite color was blue. pnicole was a very loveable erson. pnicole touched many people pthroughout her short life. pi can't do that part. p>> reporter: while authorities pwait for the results of an pautopsy they have concluded that pnicole was using a messaging app pcalled kick to communicate with peisenhower, raising questions pabout possibly dangerous pencounters. p>> i'm willing to say kick is a pdevil for young children. pit's like a free ability to ptext. panything you want. arents can't see the phone pnumbers that are coming in and pout. pthese anonymous apps are popular pwith teens and predators. p>> you can sign up as anybody pyou want to be. pit really becomes a private phunting preserve for some of pthese pedophiles. p>> reporter: here's how kik pworks. pdownlo

dr. mary ellen o'toole: that's a really stunning comment. there's a great deal of callousness? nicole's childhood friend kari cook says she noticed nicole was posting pictures on facebook claiming to be dating an older guy. 21;00;27;49 i went to the officer at my school and wrote down his name and handed it to him. the blacksburg police department responding denying she had alerted the officer, saying if a student had reached out, the officer: "would have acted on it through the 21;15;03;00 did you make this up? no. 21;14;15;18 i think if he would have done something, he would have seen all the guys on her facebook. he would have seen and he could have stopped all this. it's been nearly two weeks since nicole went missing - authorities say investigators tracked the last messages from her phone to eishenhaur. the former track star admitting to police that he communicated with the 13 year old.. saying he saw her the night she disappeared.. but saying he left.. and went to a close close friend? natalie video posted on youtube in 2014. keepers father-an aerospace engineer- the hear

dr. mary ellen o'toole: that's a really stunning comment. there's a great deal of callousness? nicole's childhood friend kari cook says she noticed nicole was posting pictures on facebook claiming to be dating an older guy. i went to the officer at my school and wrote down his name and handed it to him. museum. winston will be coming with me on friday. a couple of his pictures are attached and his short bio is below. " my name is winston and i'm a young lab mix. i'm a high energy type of guy who loves to run and play; tug-o-war, ball, you name it and i'll play it! i'm good with other dogs and bigger kids; with all my bouncing around i am a bit much for the smaller kiddos. i'm just a big puppy needing attention and activity. come down to high sierra animal rescue for a play-date with me. we can take a little walk and get to know each other better. you might just want to pack me up and take me home with you!" we also have mission: pawsible coming up on 2/27/16. winston will be coming with me on friday. a couple of his pictures are attached and his short bio is below. " my name is

dr. mary ellen o'toole saying this is a complicated case with multiple motives spelling disaster. >> there's synergy that came together that made this a very lethal pair. >> a very preliminary determination of the cause of death is stabbing. >> reporter: for nicole's mother, it's too much to bear. >> her favorite color was blue. nicole was a very loveable person. nicole touched many people throughout her short life. i can't do that part. wait for the results of an autopsy they have concluded that nicole was using a messaging app called kick to communicate with eisenhower, raising questions about possibly dangerous encounters. >> i'm willing to say kick is a devil for young children. it's like a freebility to text. anything you want. parents can't see the phone numbers that are coming in and out. >> reporter: experts say many of these anonymous apps are popular with teens and predators. >> you can sign up as anybody you want too be. it really becomes a pririvate hunting preserve for some of these pedophiles. >> reporter: here's how kik works. download the appp for free, add any name and any p

dr. mary ellen o'toole. thanks for joining us this morning. so on the outside david eisenhauer, star athlete, star student, as well, now charged with first degree murder. how do you characterize it? >> well, someone as successful as he was and as admired as he was, it tends to be even easier to hide or obfuscate -- >> easier? >> -- criminal behavior. sure, people don't question it. what we call in the fbi like icon intimidation. when someone has a particular status because of their job or because of success, people don't question who they are or what they're doing, so it is sometimes much easier to hide that deep, dark secret life. >> one of the unusual aspects of this case is that he had an alleged accessory here, natalie fact. kind of unusual for a boy and girl to team up like this. >> it really is and even more unusual that you have two females in this -- you have the victim and then you have a co-offender and so it becomes even more difficult to determine what were the roles of everybody in this, but david does appear from everything i'm r

dr. mary ellen o'toole: that's a really stunning comment. there's a great deal of callousness? nicole's childhood friend kari cook says she noticed nicole was posting pictures on facebook claiming to be dating an older guy. i went to the officer at my school and wrote down his name and handed it to him. museum.