Family of Four Found Dead in Home : Crime: Police have no suspects or motive in deaths of a Granada Hills couple and two children.

A family of four was found dead in a San Fernando Valley house on Wednesday morning, victims of an apparent multiple murder. Police called the circumstances surrounding the deaths “extraordinary,” but said they had no suspects or motive.

The bodies of the family--whom neighbors and friends identified as Heewan (Keith) and Kyungjin (Jeanie) Yoo and their children, 7-year-old Pauline and 5-year-old Kenneth--were found by relatives before 10 a.m. inside their Granada Hills house.

Police said the relatives drove to the house, on a cul-de-sac called Wish Street, when the parents failed to arrive for work at a dental lab they ran in Koreatown.

Kyungjin Yoo’s brother was the first to find the bodies, said a friend of the family who requested anonymity. The brother told the friend that the couple were in the living room covered by a blanket and the children were lying dead in their bedrooms. The friend said the relatives became hysterical and did not call police right away.

Deputy Police Chief Mark Kroeker, who heads the San Fernando Valley bureau of the Los Angeles Police Department, declined to discuss how the Yoos were killed, how the house was entered or whether it had been burglarized. While declining to give specifics, Kroeker said: “This murder has a certain ring to it that is highly extraordinary. The nature and the background is an entire mystery to us.”

Mail carrier Jerry Wan said that when he arrived about 11:30 a.m. to deliver the family’s mail, the door of the white and blue wood-frame house was standing open. A neighbor, he said, told him the Yoos were all dead. Police arrived minutes later, Wan said.

Wan said the Yoos had lived in the upper-middle-class neighborhood for about a year. They were a quiet family, he said, and “seemed real nice.”

“They kept to themselves,” Wan said. “I think it was just two weeks ago that I first saw their daughter learning to ride a bike.”

As Wan spoke, Kyungjin Yoo’s mother sat on a curb nearby and wept as friends tried to comfort her.

Several neighbors reported hearing loud noises and arguing coming from the direction of the Yoo house late Tuesday night. The racket, they said, set neighborhood dogs to barking. Chul Kim, who lives across the street, said he saw unfamiliar cars parked in front of the house.

“There was yelling and screaming at the house, but I do not know why or who was over there,” he said in Korean, describing himself as a friend of the Yoos.

Another neighbor, Zoltan Ivanyi, said he heard a noise about midnight and went outside to see what caused it, but decided it must have been a dog knocking over a garbage can. There have been several burglaries in the neighborhood recently, Ivanyi noted, including one earlier this week in the same block of Wish Street.

Kyungjin Yoo, 34, was an avid gardener and neighbors said they knew her better than her 36-year-old husband because they saw her working on her front yard. But they said that of all the family members, they knew Pauline Yoo the best, because she played with other neighborhood their children.

Nicole Jensen, 10, attended the same Granada Hills school as Pauline, El Oro Way Elementary, and knew her through a tutorial program.

“She was one of the smartest kids in the class,” Nicole said.

Last year, Pauline was chosen as student of the month for high grades and good citizenship, said school Principal Calvin Lloyd. He said Pauline was a bright second-grader whose mother wanted her to enroll in the program for gifted students.

“She was a very pleasant, very joyful student,” Lloyd said.

The Yoos, who friends said immigrated to the United States from Korea in the early 1980s, had strong ties with the Los Angeles Korean-American community. They worked in Koreatown and were active members of the Holy & Grace Presbyterian Church on West Adams Boulevard, which friends and the church’s pastor, the Rev. Peter Yang, said was also the center of their social life.

Granada Hills is one of two large pockets of Korean-American population in the Valley. There are at least two other families of Korean descent living on Wish Street and the 1990 U.S. Census reported 2,857 Korean-Americans in the community overall, making up 5.1% of the area’s population.

As Los Angeles County coroner’s investigators completed their work inside the Yoos’ house Wednesday evening, a cluster of at least 25 church and family members drawn to the tragedy formed a circle around Yang, who led them in prayer.

“I prayed for the soul of Mr. Yoo and his family,” Yang said later. “I don’t understand how someone could do this.”

Times staff writers Aaron Curtiss, Richard Lee Colvin and Hugo Martin contributed to this story.