details. that was the worst day of my life that i found out about my mom. a loving couple. a romantic hike. a secluded spot. she was turning to look at the bird. it s like her feet just went out from under her. all of a sudden i hear yelling coming from downstream. there was mrs. muller floating face up. a wife falling to her death. her husband falling apart. he was panicking and shaking. crying. the evidence at the scene makes you believe something entirely different happened. he told me she fell 20 feet. where were the injuries? why did i not see what i expected to see? a search for truth in the woods and water. if your theory is right, it is. loo like she was being hunted. almost like a hare and a wolf. two chilling accounts of what happened to the mom they adored. one seemingly unsolve able mystery. you either believe crazy story a or crazy story b. both stories are crazy. which one do you want to go with? winding down a mountain in southwest col
drowning. they said they would keep you advised. reporter: a group of medical responders went up to the creek to help. but still, no heartbeat. not a breath from leslie and it was clear, she was gone. we were not going to be able to bring ms. mueller back. reporter: at the cabin, alex was wondering why his parents weren t back yet. their hike was only supposed to last an hour or so but they had been gone three hours. were you worried? not really worried as in something happened to them. it was weird they would stay out past dark. reporter: it was past 8:00 p.m. when his dad got home. without his mom. it is my dad. and, the deputy. and they come in. it is kind of a shock to see when you are expecting somebody. you see strangers coming in, instead. what do you think when you see that? not a whole lot of time. you go into shutdown mode. reporter: alex recalled husband dad seemed like he was
matthew durkan, a colorado attorney general came on board. he was on loan from the boulder county da. what was your impression? a tough case. reporter: they combed through the case file. fred s statements. leslie s autopsy and all the tests conducted at the creek. this location was a breathtakingly beautiful place in the middle of nowhere. it was the perfect place to commit a murder where nobody would see you. coming up, authorities take a close look at the scene. the defendant s story did not match up. reporter: and for the mueller kids, a shock. i was just like, why? and they said oh, we can t tell you that. reporter: a new chapter opens. but nothing in this case will go the way anyone think it is. when dateline continues.
it is not a raging river. it is not fast moving. reporter: deputy casey reported back to sheriff bruce who by that time had talked to the couple who lived by the trail and had helped fred in those first frantic moments. what they said cast a new light on that story. a little tickling at the back of their neck gave them red flags. reporter: they said fred was frantic one minute, and seemed calm the next. they said the vibes were all wrong from him. they became very uncomfortable. did they in hindsight think back? or was it right then? they were immediately concerned. thatsomething was amiss. reporter: it was the husband, justin, who found leslie s body in the creek, but he told the sheriff fred had sent him down to search too far downstream. he drove up a short ways.
although so-called evidence that proved fred s story was possible, the defense that it was useless. the testing you did in 2009 will not be reflective of what did or did not happen in 2008. the bottoms of the creek change, the walls of the creek can change, there was erosion of crete. every time you go up there, it seemed a little different . and the defense attacked the state s expert for what it said was another lot with the mannequin test. they did not start that test with the mannequin falling from the ledge, right? absolutely not . and therefore, your testing did not account for any kinetic energy that would have been initiated from the fall, correct ? that s correct. and what about fred s story? a jumpy dog distracted by a blue jay and a swan dive toward the rocky water? the defense said, it was the truth and not at all far- fetched. it is steep and angular.