gossiper s pointed fingers at melissa, ben s best friends told each other everything in me said that dawn had something to do with that. reporter: of course, just a few years back, that sort of thing would have been unimaginable to dawn and ben s best friends scott and cindy graham. not dawn. dawn the force of nature, the center of any room she was in. i don t know if it s manipulating or what, but everybody agreed with dawn. as long as dawn was happy, then we re all happy. reporter: but after five years of marriage, neither ben nor dawn was happy. and the marriage went up in flames. ben had cheated on dawn. i could see that. this probably wasn t going to be something she was ever going to get over. reporter: dawn changed after that said cindy, didn t seem to want to act like a parent anymore. she met a guy and she would stay the night at his house. i mean when her kids are calling
gossipers pointed the fingers at melissa, ben s best friends told each other. everything in me said dawn had something to do with it. a few years back that, thinking would be unimaginable to their best friends, scott and cindy graham. not dawn. dawn the force of nature, the center of any room she was in. i don t know if it s manipulating or what, but everybody agreed with dawn. as long as dawn was happy, we are all happy. after five years of marriage, neither den nor dawn was happy and the marriage went up in flame. ben cheated on dawn. i could see that. this probably was not going to be something she was ever going to get over. dawn changed after that. didn t seem to want to act like a parent anymore. she met a guy and she would stay the night at his house. when her kids are calling saying
reporter: dawn, dawn oxley, ben s ex-wife, alyssa s mother. gossiper s pointed fingers at melissa, ben s best friends told each other everything in me said that dawn had something to do with that. reporter: of course, just a few years back, that sort of thinking would have been unimaginable to dawn and ben s best friends, scott and cindy graham. not dawn. dawn, the force of nature, the center of any room she was in. i don t know if it s manipulating or what, but everybody agreed with dawn. as long as dawn was happy, then we re all happy. reporter: but after five years of marriage, neither ben nor dawn was happy. and the marriage went up in flames. ben had cheated on dawn. i could see that. this probably wasn t going to be something she was ever going to get over. reporter: dawn changed after that, said cindy, didn t seem to
reporter: dawn, dawn oxley, ben s ex-wife, alyssa s mother. gossiper s pointed fingers at melissa, ben s best friends told each other everything in me said that dawn had something to do with that. reporter: of course, just a few years back, that sort of thinking would have been unimaginable to dawn and ben s best friends, scott and cindy graham. not dawn. dawn, the force of nature, the center of any room she was in. i don t know if it s manipulating or what, but everybody agreed with dawn. as long as dawn was happy, then we re all happy. reporter: but after five years of marriage, neither ben nor dawn was happy. and the marriage went up in flames. ben had cheated on dawn. i could see that. this probably wasn t going to be something she was ever going to get over. reporter: dawn changed after
welcome to dateline, everyone, i m lester holt t is one of those cases that everien thought they knew the answer to a husband murdered in the middle of the night it seemed strange no one else in the house that night was hurt, including his wife, sleeping by his side. stranger still was who the killer ultimately tushd out to be. here s keith morrison. reporter: it was cold the night the full moon rose, february cold in the desert valley that spilled down from reno, nevada. and in that moonlight all silver pale you the wind in the dead of night you worried at the gray end of grass, wind a cry around the corner of the house, whistled past the unlocked door. something evil afoot. something here inside. where the moon peered through the window and into the master bedroom. a little after the 3:00 in the morning. this is a case built on lies and deception and cat and mouse. who knew what it was? reporter: but the story, when it began back in 2005, was about love or what cert