Police officials here, appalled at one extended family's 20-year record of more than 200 arrests, have asked a court to remove all 10 children from the family and put them in foster homes.

The case, initiated after 8- and 9-year-old cousins were caught shoplifting toys, has forced the temporary removal of three children and created legal bedlam involving as many as eight court-appointed attorneys.

It appears to be the first case of its kind in the United States that seeks to take children away from their parents primarily because so many of their close relatives have criminal records.

A 35-year-old police juvenile officer who instigated the case, with the concurrence of his superiors, sees it as a way to goad the legal system into "breaking the cycle of crime" in this poor urban family.

"I decided we had to do something, whether it worked or not," said Pasadena police agent Thomas L. Corey.

He initiated the case last fall, when the cousins were caught stealing two toy motorcycles and a toy car at Pasadena shopping mall. And he remembered his numerous other contacts with other members of the same family during eight years on the force.

"If we did not do something, there was a 99 percent chance those children would become criminals," he said.

The cousins' grandparents, uncles, aunts and parents have been in and out of jail and prison for offenses including robbery, burglary, assault, larceny and prostitution, although there is no available record of them beating their children.

According to records compiled by Corey, 13 adults in the family have been arrested a total of 201 times since 1959, and several of the older grandchildren are in frequent trouble with the police.

The family members have fought the removal vehemently, protesting their love for their children. When police temporarily removed a 14-month-old baby from its mother's home, without food or electricity at the time, the mother screamed, "I carried that baby nine months. I had labor pains for that baby. I've stolen for that baby. I've gone to jail for that baby. I've gone through changes for that baby. You can't take him away from me."

Found today staying with four other friends and relatives in a ramshackle one-bedroom apartment here, the 27-year-old mother of one of the cousins accused of shoplifting strenuously objected to Corey's efforts.

"It's kind of bad here," she said. "We've been through a whole lot, but they don't have the right to do that. I'm going to get my son back." Now unemployed but looking for work, the tall, slender woman, said her record of 21 arrests "was not trouble we caused, but the environment we are running with."

At about the time her son was caught, she was serving 90 days in jail for shoplifting. Her son's father is in the state prison at Chino. The judge hearing the case for removal of the children, Los Angeles Juvenile Dependency Court Judge Elwood Liu, asked that names and other identifying details not be used in accounts of the case in order to protect the children from harassment.

Fred Darvey, a court-appointed attorney representing the grandmother of the family, said "I've never seen anything like" the case. He said the charges of criminal background in a dependency case "are just too nebulous, it leaves too much to the police. . . . Any parent who was arrested they could come in and take their children. That is scary to me."

Corey has spent several weeks going through about 400 individual police reports on the family, now stacked around the floor of his small office. His own report on the case includes a detailed family tree and a history of the family that goes back to the birth of the young cousins' grandmother in Waco, Tex., in 1935.

Corey said he decided to pursue the case not because of inadequate housing. "I've seen worse," he said. Even the lack of parental supervision was not as important to him as the fact that all the adult role models in the family were criminals.

In effect, the social service officials going to court in support of Corey's efforts are seeking a redefinition of what constitutes an unfit home so that a new definition would include the criminal records of the adult members.

Hunter Hurst, director of the National Center for Juvenile Justice, an organization in Pittsburgh, supported mostly by foundation grants, said the case appeared to be an extension of the common practice of removing children from homes for "emotional neglect."

Children of prostitutes are often taken away for that reason, he said. He said social workers and police were usually successful in removing the children from such homes. "But dreadfully unsuccessful in preventing the social dependency [on a crime-ridden culture] that the action is designed to prevent."

The Los Angeles Department of Public Social Services, relying on the child-neglect provision of the state welfare and institutions code, filed petitions for out-of-court placements for four children under 10, and asked that they be taken from the home pending outcome of the case.

Petitions for eventual removal of six other children 11 to 18 have also been filed. The court left one baby with his mother, and assigned one of the shoplifting cousins to live with his father's mother.

The other cousin and a younger brother were placed in a state juvenile hall after their mother, asked where they would live if they remained in her custody, gave a fictitious address.

The police force of Pasadena, a suburban city of about 100,000 only 10 miles from downtown Los Angeles, has a reputation for gentler treatment of minorities than does the Los Angeles Police Department, and Corey said he hesitated at first to pursue the case because the family involved was black. "I knew they'd throw that back at us in court, and they have. If they had been white, I would not have waited nearly as long."

The family has lived for more than two decades near a notorious intersection called "The Pit" in northwest Pasadena's predominantly black and Hispanic neighborhood. The intersection is a popular center for sale of the drug PCP, which has been responsible for or involved in many arrests of the family.

According to a family history Corey compiled, the grandmother, now 46, moved to Pasadena during childhood, and had her first child by her husband, whose family had moved here from Mississippi, when she was 17.

The husband, no longer living with her, worked as a garbage collector, and has been arrested 12 times, with many of the incidents involving family violence. The grandmother was first arrested in 1966 for throwing a lye-like substance on two women she found talking with a male friend of hers.

Corey has criminal records of arrests for nine of the woman's adult children, and she has been arrested 10 times, mostly for theft and drug sales. According to his report, she has served only two days in jail, for shoplifting.

Corey said teachers at the school which two of the cousins attended were enthusiastic when he said he would try to remove them from the family home.

Corey said they were "good kids" who appeared to like the attention and structured life at school and usually got themselves on the school bus without much help from adults. "They were very vague as to what kinds of food they had in the evening and when," Corey said.

Ten years ago, Corey said, one of the grandmothers' sons, now 23, came to the attention of two police officers who took him under their wing. "They took him home weekends, got him involved in Explorer Scouts and provided remedial tutoring," Corey said. Pasedena police began to refer to him as the "million-dollar kid," but he has turned out well and now operates a large janitorial business.

"I don't think we could afford to do that much for everybody," Corey said. "When he was a kid, the officers bought him a bicycle so he wouldn't have to steal one. They even bought him a watch, but some other member of the family stole it while he was sleeping."