"I never wanted to put him in prison," Mr. Pologruto said. "But I think he tried to completely do me in with the knife. They are ignoring it. The parents are ignoring it. Everybody's ignoring it."

Mr. Zimmerman maintains that Mr. Haffizulla was trying to commit suicide and was trying to explain that to Mr. Pologruto so the teacher could explain it to the boy's parents. In Mr. Haffizulla's mind, Mr. Zimmerman says, the 80 on his physics quiz had jeopardized his dream of being accepted at Harvard Medical School.

At the time, Mr. Haffizulla's heavy course load included four honors classes and three advanced college-placement courses.

The court heard testimony that Mr. Pologruto had tried to grab the knife, wrestled with Mr. Haffizulla and was injured when he fell on top of the student and the knife.

An expert hired by the defense testified that the wound near Mr. Pologruto's collarbone was consistent with Mr. Haffizulla's assertion. But Mr. Pologruto testified that the student had lunged at him from behind the physics lab and that he had had to wrest the knife from the student to avoid being more severely injured.

Five psychologists and psychiatrists appointed by the prosecution and defense agreed that Mr. Haffizulla was psychotic at the time of the stabbing.

At the American Heritage School, Mr. Haffizulla took fewer courses, but continued taking advanced courses, and raised his grade point average to 4.614. Perfect scores in regular classes would result in a 4.0 average.