The Oregon man and his girlfriend accused of killing the man's father and stepmother in Everett this month now have been linked to four slayings in three states.

David Joseph Pedersen, 31, and Holly Ann Grigsby, 24, are the subject of police investigations in Oregon and California, in addition to Everett, authorities said Monday.

The couple are being held in lieu of $1 million bail each in the Yuba County, Calif., jail after their arrests Wednesday. They are expected to be extradited to Washington and Oregon to face murder charges.

Pedersen, who has spent nearly half his life in Oregon prisons, and Grigsby are suspected of shooting David "Red" Jones Pedersen, 56, and stabbing to death his wife, Leslie Pedersen, 69, in Everett last month.

Police say the pair then drove from Everett in the slain couple's Jeep Liberty to Oregon, where they encountered 19-year-old Cody Myers at a jazz festival near the coastal town of Newport. Myers was shot in the head and chest outside Newport, and his body was found Wednesday miles away, police say. The couple took his car.

The Jeep, with David Jones Pedersen's body inside, was found Friday beneath a steep logging road deep in the Cascade Mountains.

On Monday, Eureka, Calif., police said a fourth slaying has been linked to the couple. Reginald Alan Clark, 53, was found dead from a gunshot wound to the head Friday.

Snohomish County prosecutors have charged the pair with two counts each of aggravated first-degree murder.

The younger Pedersen told a California newspaper that he killed his father for molesting his sister when she was younger. He told The Appeal Democrat in Yuba City that he did it because it was "his responsibility to make sure it didn't happen again."

He also said Grigsby was involved in the killings of his father and stepmother only under duress and should be absolved of any crimes.

"She's been misportrayed," he told the newspaper during a jailhouse interview Sunday night.

"Everything that's been reported I take full responsibility for. It's something I did and Ms. Grigsby had nothing to do with," he said.

The Appeal Democrat reported Pedersen declined to talk in detail or admit outright to the other killings.

Everett police Sgt. Robert Goetz told The Associated Press that officers have not looked into the molestation allegations but planned to do so.

On Sept. 26, the elder Pedersen was seen leaving his home with his son and Grigsby. Father and son had been estranged for years, Everett police say. The son had been released recently from an Oregon prison.

Based on interviews with Grigsby, Everett police said the elder Pedersen was shot in the head while driving his son and Grigbsy to the Everett Transit Station to catch a bus.

The pair returned to the elder Pedersen's home in South Everett, where they killed the man's wife for failing to do anything about the alleged molestation, Grigsby told police. She told investigators she killed Leslie Pedersen using two knives, police said.

Leslie Pedersen's body was found in the couple's Everett mobile home two days after the suspects were seen leaving with the elder Pedersen. Police say her hands were duct-taped, her head was wrapped in a blood-soaked pillow and there was a sword beside her body.

Pedersen and Grigsby were arrested Wednesday in California while driving Myers' white 1999 Plymouth Breeze four-door, police said.

Grigsby has convictions in Oregon for theft and identity theft, records showed.

David Joseph Pedersen has spent most of the past 14 years in prison.

He was sentenced in 1997 to nearly six years in an Oregon prison on robbery convictions, according to Oregon Department of Corrections records and federal court records.

In 1997, Pedersen was sentenced to serve 70 months in state prison in Oregon for two robbery charges, according to officials at the Oregon Department of Corrections and federal court records.

While in state prison, Pederson — in 2001 — was convicted in federal court for threatening to assault and murder a U.S. District Court Judge and mailing threatening convictions. He was then transferred to federal prison to serve a 24-month sentence.

While in federal prison, Pedersen received an additional 90-month prison term in Oregon state prison that stemmed from an assault he committed while incarcerated in state prison.

After he completed his federal prison term, he was transferred back to state custody, and after finishing his 90-month prison term he was released in May of 2011.

So Pedersen was in continuous custody from March 11, 1997 to May of this year. There was no early parole.

It is unclear if he was involved in gang activity while in state prison, according to a state Department of Corrections official.

Police say Pedersen has a martial-arts background; a YouTube video shows him losing a mixed-martial-arts contest in 13 seconds in mid-September. His official record is 0-3, according to the website mixedmartialarts.com.

Seattle Times reporter Hal Bernton contributed to this report, which includes information from

The Associated Press and

Seattle Times archives.

Nancy Bartley: 206-464-8522

or nbartley@seattletimes.com