Ten days ago, Kristi Kauffman, 14, a Prince William County honor student and soccer team standout, jumped in front of an approaching freight train and ended her life.

The death shook many students at Osbourn Park High School in Manassas, where she was a popular freshman. But another jolt was yet to come.

Shortly before the teen-ager swallowed a soda bottle full of vodka and stepped in front of the roaring train, she told friends that her adoptive father had sexually abused her, Prince William County police say. Investigators say the athletic girl left a journal that chronicled in detail three years of sexual abuse.

Armed with the Kristi Kauffman's journal, county police charged her 43-year-old father with aggravated sexual battery.

Paul J. Kauffman Jr. of 5360 Macwood Dr. in Woodbridge was arraigned Wednesday in Prince William County Juvenile and Domestic Relations Court. Kauffman, who legally adopted Kristi 10 years ago after marrying her mother, entered no plea.

Kauffman's lawyer, John Kilcarr, would not say yesterday how his client intended to plead in the case. Kauffman could not be reached for comment at his home or at the automobile dealership where he works. A preliminary hearing on the charge is scheduled for May 7. He is free on $10,000 bond.

Kristi Kauffman apparently never spoke of being abused to any adult -- not a teacher, counselor, hot line volunteer or even her mother, investigators said. But her friends said she had talked often of suicide. Her friends also said they did not take the threats seriously.

The diary, which was handwritten in a school notebook, showed "she was feeling a lot of anguish," said Prince William Commonwealth's Attorney Paul Ebert, who is prosecuting the case.

That anguish was not apparent to the adults who knew Kristi Kauffman. Osbourn Park High School Principal Jack Lynch said she never sought help or hinted at her troubled mind. Her mother, Ebert said, apparently was unaware of the alleged abuse, and "is very supportive of her husband."

To most teachers, she was one of the top students at the school and was considered the best player on the girls' junior varsity soccer team, Lynch said.

"Kristi was basically a model student," said Lynch. "She seemed to be the type of kid the kids went to when they had a problem."

But some of her friends now say that Kristi Kauffman sometimes said "wild things" and "had given a lot of warning signs," according to Linda Bergold, one of eight counselors brought into the school to talk with troubled students after the death of their peer.

As Ebert recounted the story that investigators have pieced together, young Kristi Kauffman's journey toward death began Easter Sunday, when she stole a bottle of vodka from her grandmother. She poured it into a soda bottle, and on April 1 a girl not known to her friends as a drinker consumed enough vodka to render herself legally drunk.

After lunch, she wandered into her gym class late, wearing some street clothing along with part of her gym uniform. She left midway through the class. The teacher did not see her leave, but two friends followed her out of the gym.

Kristi told her friends that her father had molested her and she planned to kill herself, then headed across the green lawn behind the school for the railroad tracks behind a screen of trees.

One friend, a boy, ran for help. Another, a girl, tried to grab her, but Kristi pushed her away, Ebert said.

She jumped in front of a northbound Norfolk Southern Railway train, one of about 10 trains that pass the school each day. She was killed instantly.

Prosecutor Ebert said his case will hinge on hearsay testimony and a novel legal plea that the dead girl's diary be admitted into evidence. He said his argument is unprecedented in Virginia, but has been used successfully in other states.

Hearsay evidence usually is not permitted in court because the person who made the statement cannot be questioned directly. But Ebert said Kristi Kauffman told her friends shortly before she ran off to kill herself that her father had molested her and that "she was going to end it all." Ebert said he believes that statement qualifies as a "dying declaration" -- a statement made in expectation of death, and therefore considered more trustworthy.

"The tragedy in this was that there were many opportunities to intercede," said Ebert. "If anything comes out of this, I hope young people will realize the seriousness of what can occur. If someone is contemplating doing harm to themselves, maybe they'll go to someone in authority."