LOS ANGELES (AP) — DNA evidence has linked an air conditioning repairman to the stabbing deaths of three women, including a former girlfriend of actor Ashton Kutcher, police said Friday.

Michael Gargiulo, 32, of Santa Monica has been in custody since July for a separate knife attack and could face murder charges as soon as next week, police said.

Santa Monica police Lt. Darrell Lowe said DNA collected from a crime scene last spring helped link Gargiulo to the stabbing deaths of women from Los Angeles, suburban Chicago and Monterey Park.

One of the cases involves 22-year-old Ashley Ellerin, Kutcher's former girlfriend, who was found dead in February 2001 in her Hollywood Hills home.

Kutcher, who starred in the television series "That '70s Show" and is married to actress Demi Moore, told police he went to pick up the fashion student-model for a post-Grammy Awards party, but she did not answer the door. He checked a back window and spotted what he thought were red wine stains on the carpet and then left. Her body was discovered the next day by a friend.

Kutcher's agent, Stephanie Simon, said the actor had no comment.

Police said they have a DNA match that links Gargiulo to another fatal stabbing of a Monterey Park woman in 2005. They also suspect Gargiulo in the 1993 killing of a high school girl in the Chicago suburb of Glenview, where Gargiulo lived at the time. Tricia Pacaccio, a senior at Glenbrook South High School, was found stabbed to death on her front doorstep, clutching her door key.

Gargiulo was being held in lieu of $1.1 million bail on attempted murder and burglary charges stemming from the April 28 stabbing of a Santa Monica woman in her home, Lowe said. Detectives matched a DNA sample taken from blood at the crime scene to Gargiulo. Lowe said further database cross-referencing found that Gargiulio's DNA matched genetic evidence in the three killings.

Gargiulo's attorney, Anthony Salerno, said his client denies involvement in any of the attacks and "thinks the police are out to get him."

Salerno acknowledged Gargiulo will possibly be charged with murder for the three slayings. He said that Gargiulo lived near the four victims at the time of the attacks and a garment of his was found in one of the victims' homes. But, he said, that does not make Gargiulo guilty.

Salerno said he was not aware of any DNA matches in the three killings and questioned why police have taken so long to charge Gargiulo. "If there is any DNA evidence, that would be a surprise to me," he said.

He said Gargiulo has pleaded not guilty to the attempted murder and burglary charges from April and is scheduled for a pretrial hearing Sept. 4.

When asked about the Pacaccio case, John Gorman, a spokesman for the Cook County (Ill.) state's attorney's office, said he could not talk about an open investigation. "I can't comment on any evidence that may be out there," he said.

Meanwhile, Los Angeles police are using DNA evidence to track down another suspected serial killer in Southern California. A special police task force has linked the fatal shootings of 10 black women prostitutes and one black man in South Los Angeles to one assailant who has been killing since 1985. Police said they have no known suspect because the DNA does not match any sample in national crime databases.

One victim survived an attack in 1988, giving police the only description they have of the suspect: a black man in his 30s driving an orange Ford Pinto.

The last killing in the series occurred in January 2007 with the discovery of 25-year-old Janecia Peters' body. DNA tests showed she was killed by the same assailant as the others.

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Associated Press writer Deanna Bellandi contributed to this report.