An attorney for the man accused of killing two women in Southern California in 2001 believes testimony given by actor Ashton Kutcher may prove his client is innocent.

In closing arguments in the alleged “Hollywood Ripper” murder trial, defense attorney Daniel Nardoni argued that two other men could be responsible for the stabbing deaths of Ashley Ellerin and Maria Bruno. His client, 43-year-old Michael Gargiulo, is on trial for the killings as well as for the death of an 18-year-old in his hometown of Glenview, Ill., in 1993 that is being tried separately.

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Previously Kutcher testified that he was an acquaintance of Ellerin in 2001 when she was 22. The actor was planning to take her out on a date the night she was killed, but was late arriving to her home. When no one answered the door, he assumed that she went out for the evening without him. He testified that he peered in the window and saw what he thought were wine stains before leaving.

"Ashton Kutcher is a celebrity star in the entertainment industry," Nardoni said. "And I believe Ashton Kutcher is the star witness in this case."

Kutcher was a few seasons into "That '70s Show" and had just starred in the film "Dude, Where's My Car?" He was not yet the household name and tabloid staple that he would become a few years later after marrying Demi Moore.

Ashton Kutcher testifies in the murder trial of Michael Gargiulo in Los Angeles Superior Court. A prosecutor says four strikingly similar attacks on women in California were all planned and executed by a skilled serial killer who studied the lives and homes of victims who lived near him before savagely stabbing them, in his closing remarks to the jury Tuesday, Aug. 6, 2019.  (Genaro Molina/Los Angeles Times via AP, Pool, File)

Ellerin was a 22-year-old fashion design student.

The two last spoke at 8:24 p.m., when Kutcher testified that he told Ellerin he was running late and Ellerin told him she had just gotten out of the shower.

Nardoni told jurors that Ellerin's apartment manager, an aspiring actor, testified that he was having a sexual relationship with her, and was in the house when Kutcher called. Nardoni told jurors the call could have made him angry and violent.

A neighbor who was passing Ellerin's house on the way to a nearby dog park testified that he heard two screams coming from Ellerin's house at about 8:30 p.m., just around the time of Kutcher's call. Nardoni said this was most likely when Ellerin was killed.

Nardoni told jurors he did not need to prove that someone else killed Ellerin, only to establish that another possible suspect could cast reasonable doubt on Gargiulo's guilt.

The lawyer used the same tactic when discussing the other murder his client is charged with — the 2005 killing of 32-year-old mother of four Maria Bruno in her house in the Los Angeles suburb of El Monte. Nardoni suggested that her estranged husband, the last person to see her alive, was responsible.

He showed jurors a graphic crime-scene photo of Bruno, who — like Ellerin — had been stabbed dozens of times. Bruno's breasts were cut off and breast implants removed, a sign of deep-seated hatred, Nardoni said.

"Whoever did this, it was personal," Nardoni said.

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The attorney told the jury that no physical evidence, no DNA, no fingerprints, no hair samples, were found tying Gargiulo to the scene in the Ellerin case. And he said only a shoe-covering bootie that Gargiulo used in his work as an air conditioner repair man with his and the victim's DNA was found in the Bruno case, but it was outside her apartment in a complex where both she and Gargiulo lived.

Gargiulo lived near or knew the victims in all the attacks, including the 1993 killing of Tricia Pacaccio, for which Gargiulo is awaiting a separate trial.

Defense Attorney Daniel Nardoni, left, questions Ashton Kutcher during his tesitimony in the murder trial of Michael Gargiulo in Los Angeles Superior Court, Wednesday, May 29, 2019. Gargiulo, 43, has pleaded not guilty to two counts of murder and an attempted-murder charge stemming from attacks in the Los Angeles area between 2001 and 2008, including the death of Kutcher's former girlfriend, 22-year-old Ashley Ellerin.  (Genaro Molina/Los Angeles Times via AP, Pool)

The physical evidence is far stronger for the attempted murder case, in which Michelle Murphy was attacked in 2008 in her bed at her apartment in Santa Monica, but fought back, causing the attacker to cut himself and leave a trail of blood as he fell. The DNA in the blood matched DNA collected from Gargiulo during another murder investigation.

Nardoni made no attempt at a defense on that count, essentially conceding it and telling jurors not to let it influence their decision on the two killings.

"I know that the evidence is much stronger with Michelle Murphy, that's the elephant in the courtroom," Nardoni said. "You have to judge each case separately."

Another defense attorney, Dale Rubin, cited the testimony of a defense psychologist who diagnosed Gargiulo with dissociative personality disorder, formerly known as multiple personality disorder. Rubin said Gargiulo may have been in a "fugue state" and didn't know where he was when he was in Murphy's apartment.

Gargiulo was arrested weeks after the Murphy attack, and it eventually led to charges for the two California killings and the slaying of 18-year-old Pacaccio, a friend's older sister when Gargiulo was 17.

The prosecution praised Murphy's toughness and resolve in its closing arguments a day earlier.

"Michelle Murphy, because of her strength and courage, allowed investigators to work backwards to find the killer of Tricia Pacaccio, of Ashley Ellerin, of Maria Bruno," Los Angeles County Deputy District Attorney Garrett Dameron said.

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Jurors are expected to begin deliberations on Thursday, after prosecutors give their rebuttal to the defense's closing argument.

The Associated Press contributed to this report