>> i have one lady in my class lost 110 pounds, caylee, she lost 110 pounds in one year. >> wow!hat? >> what do you say to that 280-pound person who say i don't have moves like that guy, no way i could do it. >> sit down and enjoy the class because at ktx fitness you not only get a workout but a show. that was your warm-up. >> a lot of videos online of sibling rivalry, right? what about pure love between siblings? those who shot this video turn out to be fans of "right this minute." check this out. >> yeah! yeah! >> that's little 1-year-old marisa taking her first step. and that's her big sister, kyra, jumping up and down in the background saying, yeah, yeah, yeah. now this video's older because ky kyra's now 11 and marisa is now 8. but mom and dad uploaded this video and just really introduced the sisters to this spectacular moment. but the best part is yet to come. >> marisa. >> you did something cool, marisa. >> she's going to have the best big sister in the world. >> in the video, the whole family's getting into this. >> this is little baby e oliver and grandpa bob. they deci

i remember in the casey anthony case, when they found caylee's remains, they mapped for dozens and dozense circumference of that search was massive, same issues you were mentioning. they wanted to know the progression of how those remains ended up where they ended up. are they getting soil samples to check his sneakers, getting tire track and footprint smpls to see if they can match the patterns of his tire or whatever car he might have been in? you can't walk there. >> that's possibly what they're doing. also what they're not going to be doing -- a lot of people think they should be -- that's looking for trace evidence on these bones. her beena is not even on top of these bones anymore. the only way you get the dna is within the cells of the long bones themselves. his dna is long gone. we would be looking for dna evidence under her nails. those are long gone. it's going to be humidity and heat. since the day she's gone, there's been at least four inches of rain in that area, if my calculations are correct when i did that. and there's at least six days where it's been over 80 degrees, 25

. >> reporter: from the moment 14-year-old caylee snaps a selfie. >> you can put filters on it. >> reporterute caption. >> i'll put it as good morning america crew and selfie with abby. and post it on instagram, her quest for 100 likes begins. it's called the 100 club and teens are becoming obsessed. >> if you are more popular at school then you'll get more likes an that picture. >> reporter: the concept is simple. hitting 100 or more likes shows your friends how popular you are. anything less than 100 likes is considered a poor showing, even embarrassing. like this pic of the back of kayla's head she posted that only got 70 likes. >> i'll delete the picture. >> why would you delete it? >> just because i guess the picture wasn't good enough. >> reporter: her friends are feeling the pressure, too. >> everyone in school gets around 100 or more so then kind of gets us wanting to be in the hundreds. >> it's just not good to be the only person who doesn't have it. >> reporter: and all of this anxiety worries kayla's mom. >> if it comes up while we're together i say it doesn't even matter. a pict