very rare. two suspected killers on the hunt. hunting them, a detective devoted to justice and more. it s almost like you ve adopted these young women. there s a lot of visits to my local church saying, please don t let me screw this up. hello and welcome to dateline. they were young women with their whole lives ahead of them. then, one by one, they started to vanish. it would take a determined detective willing to go into dark places to uncover the diabolical plot behind the disappearances. here is keith morrison with good and evil. how do you measure a mother s love or gauge the voracity of her impulse to protect? i love her as much as i could. it was about the only thing. how to measure love as visceral as the beating heart in her own body. she was my first you born. she was my best friend. how to understand the four mothers you ll meet tonight and their connection, one that not one of them would ever have thought possible, not in a million years, a
partner in crime? we start to see how prolific they are at hunting. reporter: hunting? detective trapp gave me her word that she would find who killed my daughter. all of these women have special meaning for me. it s hard to not take it personally. there s lots of evil in this world. lots of it. we have to go to the dark places in order to find answers. reporter: how do you measure a mother s love? or gauge the ferocity of her impulse to protect? love her as much as i could is was about the only thing. how to measure love as visceral as the beating heart in her own body. she was my firstborn. she was my best friend. reporter: how to understand the four mothers you will meet tonight, and their connection. one that not one of them would ever have thought possible. not in a million years. anymore than they would have expected to meet her. their guardian angel. if i don t bring her home, who will? reporter: its a rare mystery that s truly a confrontati
partner in crime? we start to see how prolific they are at hunting. reporter: hunting? detective trapp gave me her word that she would find who killed my daughter. all of these women have special meaning for me. it s hard to not take it personally. there s lots of evil in this world. lots of it. we have to go to the dark places in order to find answers. reporter: how do you measure a mother s love? or gauge the ferocity of her impulse to protect? love her as much as i could is was about the only thing. how to measure love as visceral as the beating heart in her own body. she was my firstborn. she was my best friend. reporter: how to understand the four mothers you will meet tonight, and their connection. one that not one of them would ever have thought possible. not in a million years. anymore than they would have expected to meet her. their guardian angel. if i don t bring her home, who will? reporter: its a rare mystery that s truly a confrontati
no gasoline can beat chevron with techron. ah-ha, that s impressive. no gasoline cleans better than chevron with techron. care for your car. (spitting. thud.) nailed it! sweet! (both cars laugh) for more on tonight s game, tune in to sports net central, giants edition on nbc sports bay area right after this broadcast. giants in front 8-2, as we go to the ninth inning. the year so far for cory gearrin really good. four strikeouts. you have three of those strikeouts in two nights ago. the giants were leading 3-1, and the d backs has runners at first and second, nobody out, and he struck out three in a row. one ball and one strike to count. arenado tonight has grounded into a forced play, grounded out to short and fouled out to first. all three of those outs were versus johnny cueto. now it s 2-1. arenado s only had three at-bats in his career against gearrin, and has a home run and a single against him. giants way ahead right now, 8-2, in the ninth inning. derek law worke
i call them my girls. it s hard to not take it personally. reporter: but first, in tennesee it s gut-wrenching. there s a body lying off the side of the road. this young woman shot three times. this was a murder. a young single mom, out with friends on game day. it was packed. but as night fell, fear grew. they re asking who would want to harm your sister? was it someone that was a stranger? was it someone that we knew? i just had this weird feeling that there was something she was hiding tucked away. in her kitchen a clue to it all. on top of the refrigerator was a manila folder. did it just give you chills? it was horrible. why didn t she just tell us? reporter: did a secret lead to murder? it s got to be unimaginable. i m lester holt and this is dateline. here s andrea canning with nightfall. ã act 1 i d ask that you all close your eyes for a few minutes this morning. i d like for you to envision roane county in the middle of october.