By Bob Meadows. Frank Swertlow
Updated October 17, 2005 12:00 PM

In the early morning hours after Halloween last year, the intruder outside Leslie Mazzara and Adriane Insogna’s Napa Valley, Calif., house smoked three cigarettes while waiting for the right moment. Dropping the butts outside, cops say, he then shimmied through an unlocked window—and slashed both women to death with a knife. The grisly murders shocked residents of the genteel gateway to wine country. The two women were well-liked and outgoing, and there had not been a murder in the town in four years. Residents began bolting their doors and some even sold their homes. “The killings affected everyone,” says one local. “It was like a Halloween movie come true.”

For nearly a year, police interviewed 1,300 people and took 218 DNA samples but made no arrests. On Sept. 27, however, police caught a break: Eric Copple, the husband of one of Insogna’s best friends, turned himself in. Napa Police Chief Rich Melton said detectives had been convinced all along that the crime was not “random,” but they had only recently begun focusing on Copple. They had tried to interview him several times in the last few months, but he wouldn’t cooperate. “It became apparent he didn’t want to talk to us,” says Melton. The break in the case came on Sept. 22, when police announced the killer smoked Camel Turkish Gold cigarettes—Copple’s brand. Melton said Copple, fearing capture, allegedly confessed to his family, who then called authorities.

Mazzara, 26, was a South Carolina native and former beauty queen who moved to Napa in 2004 to be close to her mother. She worked at a winery in nearby Rutherford. “She had such a bubbly personality. When she was happy, everybody around her was happy,” says Renee Tollison, who knew Mazzara through pageants.

During the summer of 2004, Mazzara moved in with Insogna, 26, and another young woman. An avid volleyball and softball player, Insogna, 26, was a fiercely competitive type who nearly died in an auto accident when she was 16. Left with short-term memory loss, she initially struggled just to read but eventually won a college scholarship. She landed a job at the Napa Sanitation District, where she worked as a civil engineer. While there, she became fast friends with a coworker, Lily Prudhomme, Copple’s future wife. The friendship, cops now believe, may have sealed her fate.

Police say that around 2 a.m. last Nov. 1, Copple attacked Mazzara in her second-floor bedroom and that Insogna, hearing the screams, rushed in and scratched and cut Copple—leaving his blood at the scene—before he overpowered her. The third housemate, whose name hasn’t been released, escaped from her first-floor bedroom and called police.

Police have not given a motive for the murders—or even revealed whether Copple knew Mazzara—and Copple, 26, does not have a criminal record. “Eric didn’t seem stressed or depressed,” says a family friend. “He was just a normal guy.”

Two weeks after the murders, Lily organized a vigil for her dead friends. Then, at her February wedding to Copple, she asked Arlene Allen, Insogna’s mom, to read from the Bible. “I looked directly into both of their eyes and read, ‘Love is stronger than death and passion fierce as the grave,'” says Allen. “I know Lily picked those verses in honor of Adriane.”

As much grief as she feels, Allen also feels sympathy for the murders’ hidden victims. “It’s just so sad and shocking the husband of my daughter’s dear friend Lily committed these crimes,” she says. “My heart goes out to Lily and her family—and Eric’s too.”

Bob Meadows. Frank Swertlow and Ken Lee in Napa and Lori Rozsa in Miami.