Michael Gargiulo: The serial killer next door?

"48 Hours Mystery" report helps Chicago detectives charge suspect in an 18-year-old cold case after new witnesses come forward

The Boy Next Door

Produced by Josh Gelman and Doug Longhini

In May 2011, "48 Hours Mystery" reported on the 1993 murder of a young woman named Tricia Pacaccio. Now, because of that broadcast, we can report that there is finally a breakthrough for a family that has been waiting nearly two decades for justice.

The bright lights of Hollywood have always attracted the young and the beautiful. Ashley Ellerin, 22, was no exception.

For this small-town girl from northern California, life in Hollywood in 2001 was a whirlwind of work, friends and fun.

At the center of Ashley's world was a core group of close friends - Justin Peterson, Jennifer Disisto and Chris Duran.

"She was amazing. You know, just amazing," Peterson told "48 Hours Mystery" correspondent Maureen Maher.

"She was just beautiful, and fun, and spontaneous," added Duran.

When the group wasn't out having fun, Ashley spent her days as a student at the Los Angeles Fashion Institute of Design and Merchandising.

"And what were her goals and dreams at that point in her life?" Maher asked.

"I think it was basically, you know, to get into the fashion industry," said Peterson.

But out at night with her friends, Ashley found herself catching the attention of some of Hollywood's rising young stars, including 23-year-old Ashton Kutcher.

"We had hung out with him a couple of times, you know," Peterson said. "And, you know, they had... maybe gone out on a couple dates, or whatever."

"Hollywood is Hollywood," Disisto said." You know, interacting with celebrities - that is how it is. I mean, they live here."

So when Kutcher asked Ashley out for the night of Feb. 21, 2001, no one thought much of it.

"I knew they were gonna be hanging out, going to a Grammy party," Duran explained. "[He was] pickin' her up to take her to a party."

Kutcher arrived around 10:45 that night, but Ashley never answered her door. According to police interviews, before he left, Kutcher looked in the windows and saw what he thought was spilled wine on the floor. As it turned out, it wasn't wine at all.

Ashley was found by her roommate early the next morning.

"I remember it like it was yesterday," Disisto recalled. "I entered the house. And Ashley was laying across the two stairs - absolutely blue and covered in blood.

"A sense of trauma just came over me," she continued. "I thought maybe the person was still there, and I kinda ran out, and getting to the car... and calling from my cell phone, 911. ... It still traumatizes me to this day."

Los Angeles Police Department Homicide Detective Tom Small, working out of the Hollywood division, was one of the first on the scene that morning.

"Ashley Ellerin was just everybody's daughter, you know. Living life and having fun." he told Maher. "She winds up meeting somebody who's the wrong person and lost her life over it."

Ten years later, Det. Small has no trouble remembering what he found inside that house on Pinehurst Road.

"I observed quite a large amount of blood...and not too short a distance was Ashley's body," he recalled. "A lot of anger. a lot or rage. Somebody had isolated Ashley Ellerin to kill her and was very, very angry when he did it... It just was a very bad scene. Probably one of the worst I've seen."

What surprised this seasoned investigator even more was what he didn't see - any evidence that would point to a killer.

"You know, we were just looking for any type of direction or clues that would - to lead to a suspect," Small told Maher as they stand outside of Ashley's former residence.

It was Ashley's friends that gave detectives that first and only clue pointing them to a young man Ashley had met in the neighborhood months earlier.

"The information we have is that he introduced himself as a heating and air guy," Small said. "Ultimately got some additional information. Was able to come up with some photos and identify him as Michael Thomas Gargiulo."

"We had heater problems. He came in, you know, we looked at the heater," Peterson explained. "And he started telling us all the crazy stories that, you know, he was this professional boxer."

In fact, Michael Gargiulo did have a short career as an amateur boxer. But when he first arrived in Hollywood in 1998, like countless others, he had a different dream in mind.

Los Angeles filmmaker Temple Brown gave Gargiulo a small role as a boxer in his graduate thesis film.

"This was in 1999. I was a film student at USC," Brown told Maher. "I think he was perfect for that part as far as, you know, this movie goes," he said as he watched Gargiulo's scene. "He looked it. And he performed it very well."

Video: Gargiulo's screen test
Video: Gargiulo in "Boxing's Been Good to Me"

Gargiulo fit the role of a boxer to a tee, but when the camera stopped, Brown says there was something odd about him.

"I think he was withdrawn, maybe somewhat shy, even, but just kinda very quiet and I would say kinda kept to himself, didn't really talk a whole lot," he said.

And it was that same manner that began to give Ashley and her friends pause as well.

"He really wanted to be your friend more than he wanted to be dating her," according to Disisto, who said she is not aware of Gargiulo ever asking Ashley on a date.

"That's what's weird," Duran added. "He didn't seem obsessed. I mean - it's hard to explain. It doesn't seem like he was obsessed with her sexually, like, 'I want you.' He was just obsessed with...maybe a lifestyle, or her being."

Ashley's friends say he became fixated with her, showing up at the house at odd hours.

"There was one occasion when he was observed sitting in a vehicle," Det. Small explained. "The engine was running and he was just looking in the direction of Ashley's house just sitting there and it was early in the morning."

"I was walking. And then saw him sitting in his car at the end of the street with the motor running," Peterson said. "And I keep calling Ashley, like, 'Where did you find this guy? This is very odd. Why is this guy in front of our house at 2:00, 3:00 in the morning?'"

Peterson confronted him the next day when Gargiulo dropped by for a visit.

"He started to go on about how the fact that he couldn't go home last night, because the FBI was waiting for him at his home to collect DNA samples from Chicago, some case or some murder, his best friend's girlfriend was murdered, or whatever. And I said, 'Well, what do you have to hide?' And he immediately put his leg up on the couch, and started to pull out a knife that was, like, you know, strapped to his ankle," Peterson explained. "At that point, I rushed him out of the house."

Ashley Ellerin and her friends dismissed Gargiulo's story as an unlikely fantasy. What no one realized at the time was it was true.

Besides being an aspiring actor, a boxer and a repairman, Michael Gargiulo was also the prime suspect in the investigation of the murder of Tricia Pacaccio.