Oct. 6, 2005 -- -- Nestled in the heart of California's idyllic wine country, the city of Napa is nothing if not a safe place to live. Before last Halloween night, the town hadn't seen a murder in more than two years.
But on Oct. 31, 2004, that tranquility was shattered. An intruder slipped into a home, brutally stabbed two 26-year-old roommates to death -- and vanished.
A third roommate was left alive. She saw the slayings' aftermath, and for months afterward, lived in a state of terror. She spoke publicly about that night for the first time with "Primetime" co-anchor John Quiñones.
"Still I can't sleep," said Lauren, who asked that her last name be withheld. "Basically -- it was a horror movie. That's what I thought -- exactly what I thought when I was up there."
For nearly a year, police had no idea who the killer was -- until last week, when the smallest of clues turned them on to the most unexpected of suspects.
With nothing resembling a nightlife, Napa was an unlikely choice for three single, attractive, career-oriented women in their 20s.
But that was where Lauren, an all-state athlete with a political science degree, and Adriane Insogna, a civil engineer with the city's sanitation district, chose to begin their careers.
They got along so well that in early 2004, they decided to rent a house together on the west side of town. On the day they moved in, Insogna's friend Ben Katz helped out, and her other friends, Lily Prudhomme and Eric Copple, joined them for an impromptu celebration.
Later in the summer, Leslie Mazzara, a bubbly former beauty queen from South Carolina who worked as a public relations specialist, became their third roommate.
The trio settled in comfortably. However, on Oct. 28, there was a ripple in the serenity. Mazzara brought home a boyfriend in the middle of the night, and kept her roommates up with the sounds of lovemaking.
He was the first member of the opposite sex any of them had brought home for the night, and after some discussion, they eventually agreed it would be tolerated.
"I didn't put much thought into it," Lauren said. "But I just figured in the back of my head that -- yes, people would be coming over."
Three nights later, Lauren was sleeping in her downstairs bedroom when a security light tripped on behind the garage. It was between 1:30 and 2 in the morning. Her dog gave what she calls a "warning bark," but Lauren says she dismissed the security light going on as one of Insogna's cats.
Lauren quieted her dog and began drifting back to sleep when, within minutes, she heard someone entering the house and going up the stairs. She thought it might be Mazzara's boyfriend.
"I thought, 'Oh no. Not again,'" she said. But not wanting to be a spoilsport, Lauren stayed in her bedroom and quieted her dog.
Again, Lauren drifted off to sleep, until she was woken by a terrifying commotion. "I knew it was a blood-curdling, terrified scream," Lauren said. "Adriane kept screaming and, 'Oh my God, please help. Please help.'"
In total darkness, Lauren opened her door and took one step out. But then she was overcome with fear. She stood frozen, listening, until the intruder came bounding down the stairs.
"He was just flying down the stairs, breaking stuff as he came around," Lauren said. In response, she ran. But in her panic, she ran the wrong way -- out the back door, surrounded by a 6-foot fence, and no way to get out.
Lauren hid, and heard the intruder struggling with the kitchen blinds in the front of the house. Then it got quiet, and all she could hear was Insogna's pleas for help.
Without knowing if the intruder had left, Lauren went back into the house to tend to her roommate. She tried to call 911, but the line in the kitchen was dead. Nevertheless, she tiptoed up the stairs, to Insogna's room, and was met with a ghoulish sight.
The entire bedroom floor was covered in blood. Mazzara was facedown in a pile of clothes with stab wounds all over her upper body and arms.
A few feet away, Insogna was crouched behind her bed -- alive -- but no longer able to speak and rapidly bleeding to death from multiple stab wounds.
Lauren went back downstairs, her bare feet slipping in her roommates' blood, and got her cell phone. She called 911.
She fed the operator some information until that line went dead too. She realized the intruder could still be near, and dashed to her car and called 911 again while driving away.
The horrific double murder was a stunning blow to the heart of the Napa community. Police reacted by scouring the crime scene, collecting 266 items of potential evidence -- from microscopic fibers to cigarette butts.
They found what they think is the killer's blood -- a drop of it -- outside the broken kitchen window. It contained the DNA of a white male of probable north European descent.
They also interviewed some 1,300 people, and collected 200 DNA samples, but none was a match.
Meanwhile, Lauren racked her brain for clues. She was forced to ask herself painful questions: Is the killer someone she knows? Did he intend to kill her, too?
"It turns my world into looking around and having a suspicion about everybody. ... I was thinking everybody was a suspect -- any of my friends," she told Quiñones.
Her memory didn't produce any matches either, and the investigation inched along for months until police took a closer look at two cigarette butts found at the scene.
They were able to extract DNA from those cigarette butts, and it matched the blood found by the kitchen window.
In mid-August, police told Lauren that the killer is probably a smoker, and she began thinking again.
She remembered that Eric Copple, who had been there celebrating the night she and Insogna had moved in to her house -- and who later married Insogna's friend Lily Prudhomme, smoked.
She remembered Copple as a "very shy, very quiet guy ... Not very social at all." She told homicide detectives about him, and they said they hadn't checked his DNA.
A month passed, and she checked with the police again. Lauren said she was told they hadn't been able to reach him.
Police were still focused on the cigarettes, and the next day they released photos of the brand smoked by the killer. Camel Turkish Gold had been on the market just four months at the time of the murders.
Family and friends of Copple recognized he smoked that brand. Within days, Copple -- after consulting with family -- turned himself in.
The news left Lauren and her acquaintances shellshocked. In January, when Prudhomme and Copple wed, they invited Insogna's mother, Arlene Allen, to read from the Bible in the memory of her slain daughter.
Copple had even attended a candlelight vigil organized by Insogna's friends two weeks after the murders.
"I never felt that he was dangerous. I never felt any kind of a negative -- dangerous -- sinister vibe from him at all," Allen said.
Lauren says when she looks at Copple's picture now, "It's difficult. He looks like such criminal now. He was just a shy guy. He just seemed nice."
Sources tell "Primetime" that Copple wrote a suicide note that indicated he was jealous of Insogna's close friendship with his Lily.
Asked why she thought Copple didn't kill her, Lauren said, "I don't know. I just happened to have my door closed that night. That's it. That's the only thing."
She remains tortured by questions: What if she had opened that door and let her dog out? What if she had confronted the intruder when she first heard him enter? Would she also be dead?
Copple also remained at large for more than a month after Lauren gave his name to the police, but she says she doesn't blame them. She had thought about possible suspects for months.
She says she still has fear, but she is coping with the help of good friends, and exercising.
She also says she keeps a spiritual connection with her dead roommates. "The girls added something to my life. I'll never forget that. It's just -- having that chunk gone is hard to fill," she said.