A Loudoun County judge yesterday delayed sentencing for Clara Jane Schwartz, who was convicted of orchestrating her father's killing, to give her attorneys time to argue that their client was abused by Robert Schwartz, a well-known scientist.

The decision by Circuit Court Judge Thomas D. Horne came after Clara Schwartz's history teacher at Loudoun Valley High School testified that the teenager was demeaned by her father and that he often refused to give her rides to school events.

Horne delayed sentencing until Feb. 10, giving Schwartz's defense team time to prepare a written motion to support its argument that Richard Gillespie's testimony could have changed the outcome of Schwartz's murder trial. If the motion is granted, Schwartz would get a new trial.

During her October trial, prosecutors said Schwartz harbored a deep hatred of Robert Schwartz, 57, and recruited a friend to kill him. On Dec. 8, 2001, that friend, Kyle Hulbert, 18, went to Schwartz's Loudoun farmhouse and slashed and stabbed him with a two-foot sword, prosecutors said. Hulbert is awaiting trial in March.

Clara Schwartz did not testify at her trial, but her attorneys argued that she often complained about her father, a renowned expert on DNA sequencing, but never intended for him to be killed.

James Connell, one of Schwartz's attorneys, said Gillespie's testimony about the rocky relationship between the father and daughter might have "tipped the scales" for the jury.

"Robert Schwartz was portrayed as a world-renowned scientist and model father. He may be that to some people, but he was not a model father to Clara Schwartz," Connell said.

Connell noted that Schwartz's sister, Michele, testified that she never saw their father abuse Schwartz. Gillespie could have served as a rebuttal witness to contradict that, he said.

Gillespie, who knew Schwartz when she was a student and history club officer in high school, said in court that he contacted the authorities after learning of her arrest. Schwartz was a sophomore at James Madison University at the time.

Gillespie said Schwartz often missed history club events because she did not have a ride. He testified that he never heard the father and daughter speak but thought that Schwartz was "verbally abused."

Connell argued that Schwartz deserves a new trial because investigators had interviewed Gillespie shortly after the killing but did not inform the defense of the content.

Deputy Commonwealth's Attorney Owen D. Basham said that Schwartz's assertions of abuse were explored during the trial and that her attorneys could have interviewed any teachers or friends. "There's nothing here that would even remotely affect the outcome of this case," Basham said.

Outside court, Schwartz's family said they had hoped the hearing would mark the end of the case. Michele Schwartz said that her father and sister often argued but that she chalked it up to typical struggles between a parent and teenager.

"Any allegations of abuse are absolutely ridiculous," she said. "I lived with Clara and my father, and nothing like that ever occurred."

Clara Jane Schwartz was convicted of arranging the killing of her father, noted scientist Robert Schwartz.