A Grisly Double Murder Shocked Napa Valley. Three Cigarette Butts Led to the Killer’s Capture

A grisly double murder in Napa Valley haunted the community for nearly a year — until three discarded cigarette butts turned out to be the crucial evidence detectives needed.

In the early hours after Halloween in October 2005, an intruder slipped through an unlocked window into the Napa Valley, Calif., home shared by Leslie Mazzara and Adriane Insogna. Armed with a knife, the attacker brutally stabbed both women to death.

The crime stunned residents, not only because Napa Valley is widely seen as a peaceful wine country enclave, but also because the two 26-year-old victims were so well regarded.

“The killings affected everyone,” one local resident recalled. “It was like a Halloween movie come true.”

Mazzara, a former beauty queen from South Carolina, had moved to Napa in 2004 to be closer to her mother. She worked at a winery and was known for her bright, infectious presence. “She had such a bubbly personality,” said Renee Tollison, who knew her through the pageant circuit. “When she was happy, everybody around her was happy.”

That same year, Mazzara moved in with Insogna and another young woman.

Insogna was athletic and competitive, playing volleyball and softball, and worked as a civil engineer at the Napa Sanitation District. There, she became close friends with a colleague, Lily Prudhomme, who was engaged to a man named Eric Copple. Investigators would later say that this friendship may have ultimately put Insogna in danger.

The investigation dragged on for months. Detectives interviewed about 1,300 people and collected 218 DNA samples, yet no arrests were made. Still, they had one important lead: before the murders, the killer had smoked three cigarettes outside the house and left the butts behind.

Eventually, police began to focus on a suspect — Eric Copple, Lily’s fiancé. He was difficult to pin down for an interview, and investigators became increasingly convinced that the attack was not random.

On Sept. 22, 2006, authorities made a key public announcement: the killer had smoked Camel Turkish Gold cigarettes.

Days later, on Sept. 27, 2006, Copple was arrested. After realizing that investigators had identified his preferred cigarette brand, he confessed to his family and reportedly wrote suicide notes, according to CBS News, which helped lead police to him.

Investigators later said that around 2 a.m. on Nov. 1, 2005, Copple climbed through an open window into the home. He first attacked Mazzara as she slept in her second-floor bedroom. Hearing screams, Insogna rushed in to help and managed to scratch him, leaving his blood at the scene before he overpowered her. A third housemate, whose name authorities did not release, escaped from a first-floor bedroom and called police.

Speaking to ABC News, the surviving housemate described the terror of that night. “Still I can’t sleep,” she said. “Basically — it was a horror movie. That’s what I thought — exactly what I thought when I was up there.”

Investigators did not present a definitive motive, but one of the most disturbing details was what happened next: Copple later married Lily Prudhomme, Insogna’s best friend. When Lily appeared on 48 Hours to appeal for information about the murders, Copple was in the room during the interview.

District Attorney Gary Lieberstein told CBS he believed Copple harbored resentment toward the time Lily spent with her friends and felt their presence cut into his relationship with her. Lieberstein theorized that Copple, in a drunken rage, attacked the women after Lily declined to spend the night with him at their apartment.

“He claimed that while he had some memory of leaving his house and taking a knife, that he didn’t know how he ended up at the house on Dorset,” Lieberstein said. “He remembered smoking the cigarette out front, remembered going in the window but didn’t remember much else. He would not admit that he knew what he did. He knew he was responsible but he claimed his eyes were closed.”

Even after his arrest, those who knew Copple struggled to reconcile the horrific crime with the man they thought they knew. As a family friend said at the time, the murders remained baffling: “Eric didn’t seem stressed or depressed. He was just a normal guy.”