Girl Admits Murder in Diary--but Did She Do It? : Trial: Prosecution says tortured home life led her to kill her stepsister. Defense claims the admission was a fantasy.

This is a grim tale, one that begins with the death of a child, then gets worse.

Tragedy first came calling one morning in August, when a Fremont couple found their 4-year-old daughter dead in her bed. The coroner said the child had stopped breathing, but no one could explain why.

Then at Christmastime, a clue turned up right down the hallway--in their other daughter’s bedroom. In a chilling entry on Page 1 of her locked diary, the 14-year-old girl made what appeared to be an unmistakable confession:

“Dear Diary . . . I killed my sister! I went into her room and got her and took her into my room and told her I loved her and covered her mouth and suffocated her!”

Now the troubled teen-ager is on trial for murder here in the San Francisco suburbs. She insists that she did not do it, declaring that she fabricated the diary entry to give her grieving mother an explanation for the mysterious death.

Her family accepts the story, but Alameda County prosecutors are convinced they have found their killer. They charge that an “emotionally disturbed” girl murdered her beloved stepsister to “rescue” her from a home of misery, a place where molestation by her father and neglect by both parents were the norm.

“In her mind, she did the only rational thing she could, she murdered” her stepsister, Deputy Dist. Atty. Matthew Golde argued in court Thursday. Four months later, he said, the girl confessed in her diary “because she couldn’t carry that burden on her shoulders any longer.”

Melvin Belli, the adolescent’s famed defense lawyer, called the charges “pure nonsense.” The 4-year-old, he said, died of natural causes, succumbing to an acute attack of asthma that had plagued her since birth.

Belli and fellow defense attorney Shelley Antonio concede that their client suffered a tortured home life. But they say her fondness for her sister provided a vital refuge from that torment--one she would never destroy.

The two girls “were surrounded by ugliness and evil, violation and cruelty,” Antonio said during final arguments Thursday. Their mutual love “was an oasis in a hurricane of pain. . . . There is absolutely no motive, no reason (the defendant) would take a life that meant so much to her.”

A freshman at Washington High School in Fremont, the teen-ager was arrested Dec. 27 after her mother and stepfather turned her tiny green diary over to police. She remains in Juvenile Hall, and her name, along with those of her relatives, is being kept confidential because she is a minor.

Now in its third week, the trial has captivated the blue-collar city of Fremont, where the brown-haired girl was a cheerleader for a regional football league and enjoyed roller skating, romping with her dog and hanging out with friends at NewPark Mall.

“It’s the No. 1 topic around here,” Michelle Cooper, the defendant’s best friend for 10 years, said in an interview. “The sad thing is, people who don’t even know her are judging her and saying she should be locked up. I get in a lot of fights trying to defend her.”

Cooper, 15, is one of several teen-agers ditching school to sit in court and give their friend moral support. “We’re trying to cheer her up,” said Nicole Allen, 14. “She’s got a lot of problems, but she’s the kind of friend who’s always there for you.”

With its horrific themes, bizarre courtroom twists, sobbing witnesses and flamboyant defense attorney, the Superior Court trial also has been a media sensation. A TV movie is in the works, and a CBS newsmagazine crew--although prohibited from filming the trial--has equipped the lawyers with tiny microphones to record their every word.

In making his case, the district attorney relied on testimony from an Alameda County coroner, who concluded that the child died of “traumatic asphyxia,” perhaps as a result of someone crushing her back or her chest.

Dr. Paul W. Hermann also testified that the youngster had been sodomized at the time of death, or immediately before it, and that older scars indicated a history of sodomy over the past year.

Golde blamed the child’s father for the sexual abuse and noted that the defendant had once complained to police of being molested by him. That charge was investigated and dropped, and the stepfather denied the accusation on the witness stand.

Defense attorneys built their case on a simple foundation--that a murder never occurred on the night of Aug. 18, 1992. Instead, a defense pathologist testified, the child was killed by a rare and intense asthma attack.

As for the diary, Antonio called it a desperate attempt to “get her mother’s attention” and “provide closure” to her family’s endless agonizing over why their youngest child had died.

To support this contention, the defense presented testimony from a psychologist who described the teen-ager as severely disturbed and prone to wild fantasies. Psychologist Paul Berg noted that she had made two suicide attempts, had burned herself with cigarettes and had twice been hospitalized for depression.

Cooper and Allen, the girl’s friends, echoed the psychologist’s findings, noting that their friend told lots of “crazy lies,” apparently to get attention.

In an interview, her stepfather confirmed that assessment and called the teen-ager “a very disturbed child.”

“She felt a lot of guilt after the death, like, if she had been in the room with her sister, she might have been able to save her,” said the stepfather, who wears dark sunglasses and clutches a cross that hangs from his neck while in court. “Maybe she wrote that in her diary to get attention, or maybe she did it because her mother and I were walking around in a daze. I don’t know.”

The trial is being heard by Alameda Superior Court Judge Sandra Margulies, who expects to render a verdict this morning. If the judge finds the girl guilty, she could sentence her to 10 years in the California Youth Authority.