Michael Thomas Gargiulo stands accused of murdering three women, including Ashton Kutcher's then-girlfriend, Ashley.
“He slashed Ms. Ellerin’s throat so violently [he] nearly decapitated her"
And now, 14 years after her death, Ashton could be set to give evidence in the case against the alleged serial killer.
Court documents, obtained by The National Enquirer, reportedly reveal that Ellerin - who lived just 400ft away from Gargiulo - was in the shower before being stabbed 47 times.
“He slashed Ms. Ellerin’s throat so violently [he] nearly decapitated her,” the docs claim.
"After she was murdered her body was left displayed in a… demeaning pose that was sexual in nature."
Gargiulo, who is also accused of murdering Maria Bruno and Tricia Pacaccio, has been described by prosecutors as "a serial, psycho-sexual thrill killer who engages in the systematic slaughter of beautiful women because he takes sexual pleasure from manipulating, stabbing and killing his victims."
The trial, which will allegedly begin in the coming months, will reportedly see Ashton called as a witness.
The actor was reported to have given evidence at the time of Ellerin’s death, telling police that he tried to call Ellerin twice during the evening but she did not pick up her phone.
He then drove over to her apartment at 10.45pm, where he knocked on her door, but received no reply.
Giving up, Ashton left. Ellerin's body was found later by her roommate.
In an interview on 48 Hours Mystery, Ellerin’s friends revealed how she got close to Kutcher.
"And, you know, they had... maybe gone out on a couple dates, or whatever"
"We had hung out with him a couple of times, you know," her pal Justin Peterson said.
"And, you know, they had... maybe gone out on a couple dates, or whatever."
LAPD Detective Tom Small told LA Weekly: "She had tons of boyfriends. At that time Kutcher was still coming up.
"He hadn't established his big-time credentials yet. They met through a mutual friend.
"It was a friendly thing. They went out a couple of times."