Ashton Kutcher is expected to testify Wednesday in the trial of an alleged serial killer called the "Hollywood Ripper." Los Angeles prosecutors say Michael Gargiulo murdered three women including Ashley Ellerin who was friendly with the actor. Kutcher's testimony is only expected to take a few minutes but it will be the first time we've heard Kutcher speak publicly about the case.

As a prosecution witness, Kutcher is expected to help establish the time of death for Ellerin. Kutcher and Ellerin were scheduled to go out on a date on the night she was murdered. When Ellerin failed to answer her cellphone earlier in the evening, Kutcher went to her Hollywood home and knocked on the door.

During opening statements, prosecutors told jurors they believe Ellerin was attacked from behind by Gargiulo after she exited her shower on February 21, 2001. Around 10:45 p.m., Kutcher arrived to take her to a Grammys party. According to deputy district attorney Daniel Akemon, Kutcher looked in the window when he arrived at Ellerin's home and thought he saw wine spilled on the floor. "We believe now the evidence will show that was actually blood," Akemon said.

Kutcher allegedly told police, when she didn't answer the door he left. Ellerin was found brutally stabbed to death by her roommate the next morning.

Prosecutors describe Gargiulo as a "methodical and systematic" killer. He is accused of attacking at least four women, three in California and one in Illinois. 
 
Michelle Murphy, the prosecution's first witness, was allegedly Gargiulo's only survivor. Prosecutors claim Murphy battled for the knife and say Gargiulo used to stab her, cutting him, and leaving his DNA at the crime scene – DNA that was found years earlier on another victim, Tricia Pacaccio, across the country.

The family of 18 year-old Tricia was called to testify in this trial because of the similarities between Tricia's 1993 death in suburban Chicago and the three cases from L.A. County. Investigators believe Pacaccio was Gargiulo's first victim.
 
Her murder was unsolved until 2011, when two witnesses came forward after watching a "48 Hours Mystery" report on the case. Within a few weeks, Gargiulo was indicted, but has not yet been tried. His attorneys deny he killed anyone.
 
The Pacaccio family had never met the two witnesses who blew open the case until they all came to L.A. to testify. But the Pacaccios must wait for the trial in L.A. to end, before Gargiulo can be brought back to stand trial for their daughter's death.  
 
"Fighting for this case goes on with me forever. And that's the way it's gonna be," Diane Pacaccio said.