we had no confession. we had no dna. reporter: 20 years went by. i still had to keep looking for what i had lost. reporter: but cathy had her. and she had him. i put a lot of faith in god. darren was his tool. and the killer? he never had a chance. this was everything to her. i fulfilled my promise. reporter: in the wee small hours of the morning, while the whole wide world is fast asleep, mary bennett is awake. not because she wants to be, but because some things stay with you, whether you want them to or not. and for mary bennett, it s the time 3:40 a.m. every day i wake up around that time. it s embedded in my brain. reporter: for the last 21 years, that particular time has stabbed her in the heart, pulled her awake. it s an internal clock, permanently set to the worst day of her life. it began with a phone call, then a knock on the door, and news of something that should never have happened to this family, to this girl. when she would come inside the
reporter: 20 years went by. i still had to keep looking for what i had lost. reporter: but cathy had her. and she had him. i put a lot of faith in god. darren was his tool. and the killer? he never had a chance. this was everything to her. i fulfilled my promise. reporter: in the wee small hours of the morning, while the whole wide world is fast asleep, mary bennett is awake. not because she wants to be, but because some things stay with you, whether you want them to or not. and for mary bennett, it s the time 3:40 a.m. every day i wake up around that time. it s embedded in my brain. reporter: for more than two decades, that particular time has stabbed her in the heart, pulled her awake. it s an internal clock, permanently set to the worst day of her life. it began with a phone call, then a knock on the door, and news of something that should never have happened to this family, to this girl. when she would come inside the house, her favorite thing was,
dna. reporter: 20 years went by. i still had to keep looking for what i had lost. reporter: but cathy had her. and she had him. i put a lot of faith in god. darren was his tool. and the killer? he never had a chance. this was everything to her. i fulfilled my promise. reporter: in the wee small hours of the morning, while the whole wide world is fast asleep, mary bennett is awake. not because she wants to be, but because some things stay with you, whether you want them to or not. and for mary bennett, it s the time 3:40 a.m. every day i wake up around that time. it s embedded in my brain. reporter: for more than two decades, that particular time has stabbed her in the heart, pulled her awake. it s an internal clock, permanently set to the worst day of her life. it began with a phone call, then a knock on the door, and news of something that should never have happened to this family, to this girl. when she would come inside the house, her favorite thing w
dna. reporter: 20 years went by. i still had to keep looking for what i had lost. reporter: but cathy had her. and she had him. i put a lot of faith in god. darren was his tool. and the killer? he never had a chance. this was everything to her. i fulfilled my promise. reporter: in the wee small hours of the morning, while the whole wide world is fast asleep, mary bennett is awake. not because she wants to be, but because some things stay with you, whether you want them to or not. and for mary bennett, it s the time 3:40 a.m. every day i wake up around that time. it s embedded in my brain. reporter: for the last 21 years, that particular time has stabbed her in the heart, pulled her awake. it s an internal clock, permanently set to the worst day of her life. it began with a phone call, then a knock on the door, and news of something that should never have happened to this family, to this girl. when she would come inside the house, her favorite thing was,
then in 1994, out of high school and a young woman of 20, cathy started to see a boy named albert. a boy she d played with as a child, and was now interested in romantically. were they boyfriend and girlfriend? she said that they were, you know, seeing each other, but it wasn t anything serious or formal that i knew of. that s how she explained it to me, you know, he was a nice guy. reporter: cathy s plate was full that february of 1994. she was an honors student at cal state fullerton, holding down two jobs one at the local drugstore and another as a college. and now she was also seeing a new guy. just a few days before february 14th, cathy told sister tina what she wanted for valentine s day. she said, tina, i would just like it if somebody gave me a dozen red roses for valentine s day. and i said, yeah, that s all you want? she said i would just like a dozen red roses. reporter: she had never received a dozen roses from anyone, but that year she was hopeful