The Napa, CA Halloween Killing Remembered 20 Years Later

Sitting an hour north of San Franciso, the quaint suburban neighborhood on Dorset St in Napa, CA bore virtually no issues with violent crime in 2004. That’s why the entire neighborhood was shaken when, on Halloween in 2004, a beauty queen and her roommate were stabbed to death in their suburban home. 

Napa Valley appeared to be the quintessential American dream. With its temperate climate, miles of wineries, beautiful palm trees, mountains, and setting sunsets, it was the preferred spot for wine connoisseurs, tourists, and honeymooners from around the world.

How–and why–would anyone be filled with so much rage that they would kill someone and disturb all of that peace? And especially so young. Leslie Ann Mazzara and Adriane Insogna were 26 years old at the time they were murdered. Their third rooomate, Lauren Meanza (then 27 years old), managed to survive and tell the tale.

Who were they–and who was the murderer?

Who were Leslie Ann Mazzara and Adriane Insogna?

Leslie Ann Mazzara as a South Carolina beauty queen.

Leslie Ann Mazzara and Adriane Insogna moved to Napa Valley after deciding to focus on their careers. It was an unusual choice for two very attractive and stylish women in their 20s, when most of their peers were more focused on partying, socializing, and living it up. The extremely quiet, middle-class neighborhood offered no nightlife and was more than an hour north from central San Franciso.

It was perfect for their goals. Leslie was a former beauty queen who had just gone through a breakup and wanted to focus on a career in peace and quiet. She had been offered a job as a greeter for a winery run by the director of the “Godfather”, Francis Ford Coppola. 

Adriane Insogna had lived in Calistoga, just about 45 minutes north of Napa Valley. She had completed her bachelor’s degree in civil engineering at the California Polytechnic State University just three years prior to her murder. At the time of her death, she worked at the Napa Sanitation District as an assistant engineer.

The two lived a quiet, low profile life, and so did their third roommate, who lived on the second floor. The bout of drama may have been on October 28, just a few days prior to the murders, when Leslie brought home a boyfriend in the middle of the night, and kept her roommates awake as a result of the rendezvous. 

The 2004 Halloween in Napa Valley That Changed Everything

Despite the drama just a few days earlier, the home and neighborhood resumed to its tranquil atmosphere. In fact, most of the day was an average Halloween like any other. The girls gave out candy to resident trick or treaters all evening, until 11pm, when they turned off all the lights and hit the hay.

But at 2am, all three were woken by a loud sound. Lauren would later describe the sounds as shattered glass all over the lower level of the home, blood-curdling screams, and heavy footsteps throughout the home. Terrified when the footsteps started to grow louder, Lauren sneakily ducked out the back door and hid in the yard. Once she heard someone climbing out of the basement window and running off the property, she began to make her way into the home and around the staircase toward the rooms she’d heard the screaming from.

She could not believe what was in front of her.

Left: Adriane Insogna, Right: Leslie Ann Mazzara

Face down in a pool of blood roughly 2 inches deep lay her roommate and former beauty queen Leslie Mazzara. Towards the back of the bed crouched Adriane Insogna, barely alive and bleeding heavily–near death. Lauren, mortified by what she had seen, gasped, and slipped on the blood as she frantically tried to make her way out. 

The immediate question everyone had: who–and why–had someone done this?

Finding the Killer

The timeline it took for detectives to finally determine the killer was long. The cops went through every suspect relating to the girls’ former and current boyfriends, and for three beautiful, attractive young bachelorettes, the list alone was long enough. 

After 11 months, and many failed suspect DNA sampling, the police uncovered a piece of evidence strong enough to link the case with another suspect.  

Cigarette butts had been found around the perimeter of the residence. This piece of evidence was later disclosed publicly, and not even three days later, a young local man with some association with the ladies had written to his parents that he had been planning to end his life. 

He didn’t follow through with it. The family convinced him to turn himself in to the police instead. 

Eric Copple, then 26 years old, confessed to murdering both girls and was promptly arrested by the Napa Police. 

Who was Eric Copple?

Little is actually known about Eric Copple’s background. He had no criminal record at the time of the killings and he was described as a “sweet, gentler” man who was publicly adorned by his wife–even on the stand during his trial. What is known is that Copple was a local Napa Valley resident married to Adriane’s best friend Lily Prudhomme. Lily was close to Adriane, both as a co-worker and a gym partner. Overall, the friendship was relatively brief. The two had known each other a short amount of time since Adriane had moved to the area.

Mugshot of Eric Copple

“The burning question: why? What caused him to lose control and commit these horrible murders?” -Adriane’s mother Arlene

Possible Motives

The exact motive has yet to be determined to this day. Even if it was an issue he had with his wife’s friend, why so brutally murder her, and Leslie? And why try to come after Lauren next?  

The only two motives that currently stand:

• Eric was resentful and possessive over any and all relationships that Lily had that may take time away from him.
• According to Eric’s words, he had a recollection of leaving his home with the knife that night, but no memory of entering the home and what transpired afterward, effectively claiming he had blacked out. 

It’s hard to believe Eric blacked out considering he had burned his clothes and shoes that same night. He very likely knew what he was doing and the consequences of his actions.

Where Are They Now?

Despite the many unanswered questions Eric left behind, justice was served for the two girls. At 26 years old, the Napa Valley killer was convicted of two life sentences with no possibility of parole. He currently serves time at the Pleasant Valley State Prison in Coalinga, California.

Left: Adriane Insogna; Right: Lily Prudhomme Copple

The single surviving housemate, Lauren Meanza, continues to live under a low profile. Apart from a 2006 interview with the Napa Valley Register, where she admitted her healing jumpstarted seeing Copple sentenced to life, not much else is known about her latest whereabouts. As of 2023, his wife Lily Prudhomme Copple, who publicly defended her love to Eric on the stand during his trial, continues to live in the neighborhood that has been altered forever by the brutal slayings.

The neighborhood has never been the same. The area has been a fugitive hideout twice, once in 2019 and another time in 2012. It’s also been the area for several other shootings and as of 2023 has an Instagram for their police department with a following of about 11k. While it’s remained below the national average in terms of crime, it is slightly above the state’s average violent crime rate today.

Additional References

https://www.swordandscale.com/jealous-rage-to-double-murder-in-napa-valley/

https://findagrave.com/memorial/36743450/adriane-michelle-insogna

Are you hungry for more true crime? Take a look at the famous murders that changed America or other murders that changed Halloween forever.