trying to get a shot of him. journalist michael fleeman. harold gave several versions of what happened. and where the stories begin to diverge is really what was exactly happening at the time that she went off the cliff. was she taking a picture of him? was he on his cell phone looking at text messages? reporter: friends and family weren t the only ones comparing notes and clues. because toni died in a national park, the fbi joined the investigation. and the more they looked at what happened, the more reasons they found for concern. starting with the trail itself. this is not an easy descent, and people who knew toni couldn t understand why a woman who had had bad knees since high school would even risk it. dateline retraced harold and toni s path with the help of joey thompson, a climbing and hiking guide who often works in rocky mountain national park.
reporter: toni s friends at work couldn t believe it either. i got a call from christy at our office and all she said is, tammi, toni fell reporter: what did you think when she said she fell i just said, is she okay? no, she died and i fell to my knees and my husband said, oh, my gosh, what s going on? and i said, dr. henthorn fell off a cliff. reporter: everyone was heartbroken for toni harold and, most of all, the henthorns 7-year-old daughter haley. i put myself on the mountain and at the moment that she probably knew, well, this is it, you know i know her thoughts were of haley. reporter: about 150 people die in national parks each year. in rocky mountain national park, the leading cause of death is falling. before i wrote this book, i didn t know that the national park had investigators
reporter: harold told many people toni was taking pictures of wild turkeys while the ranger recalled harold saying toni was trying to get a shot of him. journalist michael fleeman harold gave several versions of what happened and where the stories begin to diverge is really what was exactly happening at the time that she went off the cliff. was she taking a picture of him? was he on his cell phone looking at text messages reporter: friends and family weren t the only ones comparing notes and clues. because toni died in a national park, the fbi joined the investigation. and the more they looked at what happened, the more reasons they found for concern. starting with the trail itself this is not an easy descent, and people who knew toni couldn t understand why a woman who had had bad knees since high school would even risk it dateline retraced harold and toni s path with the help of joey thompson, a climbing and
harold gave several versions of what happened. and where the stories begin to diverge is really what was exactly happening at the time that she went off the cliff. was she taking a picture of him? was he on his cell phone looking at text messages? reporter: friends and family weren t the only ones comparing notes and clues. because toni died in a national park, the fbi joined the investigation. and the more they looked at what happened, the more reasons they found for concern. starting with the trail itself. this is not an easy descent, and people who knew toni couldn t understand why a woman who had had bad knees since high school would even risk it. dateline retraced harold and toni s path with the help of joey thompson, a climbing and hiking guide who often works in rocky mountain national park. is this path a path well-traveled? do a lot of people come down here? it seems tricky. no. this path is way out of the way
this is a spot that most people would be too nervous to approach. the investigation begins. it was supposed to be the perfect weekend in the rockies, but the tragedy struck during a hike. toni henthorn tumbled off the edge of a steep cliff. 8:41 mountain time, her husband harold texted her family two horrible words. she s gone. i d never seen my dad cry. never. and i d say for probably the next two weeks all the time. just constant. reporter: she was his little girl. uh-huh. i can tell you it doesn t matter, you know, what age they are, you know, a parent can never accept it. reporter: toni s friends at work couldn t believe it either. i got a call from christy at our office and all she said is, tammi, toni fell. reporter: what did you think when she said she fell?