California Man and His Alleged Accomplice Charged With Slaying 4

LANCASTER, Calif. – A man and his alleged accomplice were charged Tuesday with beating and stabbing his ex-wife, her two children and a relative and then setting an Antelope Valley home on fire to cover up the crime.

Jae Hwan Shim, 39, of Palmdale, and his friend Steve Kwon, 37, of Los Angeles, were each charged with four counts of first-degree murder, one count of arson of an inhabited structure and burglary, the Los Angeles County district attorney's office said.

Shim was accused of threatening his former wife Young Park after she moved out of the family house earlier this year and moved in with her cousin in Quartz Hill. The burned bodies of Park, 34; her son Justin, 9; daughter Jamie, 13, and her cousin's husband Joseph Ciganek, a NASA scientist, were found in the house on June 23.

Meanwhile, the slain woman's boyfriend was missing and authorities were trying to determine whether he may be a victim of foul play.

Si Young Yoon, 34, of Lancaster, was a martial arts teacher for the children and Shim was upset that he was dating her, prosecutors alleged.

Yoon's Acura sport utility vehicle, with his driver's license, check book and credit cards inside, was found near the burning home, authorities said. He originally was considered a "person of interest" in the killings but investigators changed their minds.

"They do believe he may be a victim of foul play now," sheriff's Deputy Denise Fuchs said.

Shim and Kwon would be eligible for the death penalty if convicted because the murder charges carry special circumstance allegations that they committed multiple murders and killed during a burglary.

They could not immediately be reached for comment. They were being held without bail in Douglas, Ariz., near the Mexican border, after police arrested them there Saturday.

Prosecutors will seek their extradition but the process could take several weeks, said Jane Robison, a spokeswoman for the district attorney's office.

Shim, who has a beauty supply store in Palmdale, is the second husband of Park and was not the father of the two children killed. Robison said they did have a 3-year-old son together and Shim left the child in another person's care before he disappeared after the slayings.

Ciganek worked at NASA's Dryden Flight Research Center at Edwards Air Force Base, authorities said.

Within hours of the fire, sheriff's homicide detectives found Ciganek's body in one bedroom; the other victims in another. He and the children died of multiple stab wounds and blunt force trauma, the coroner's office said. Park died of multiple stab wounds.

Investigators recovered from the house a samurai sword and baseball bat they believe were used as murder weapons.