On a Wednesday morning in spring, at the Bronx Hall of Justice, Augustin Bizimungu, the former Rwandan army chief, was being grilled by a prosecutor over his role in the Rwandan genocide. He was denying his involvement, but the prosecutor pressed him about his inconsistencies.

Luckily for him, the stakes at this second trial were much lower than his first, which resulted in a 30-year prison sentence handed down just last year by the International Criminal Tribunal for Rwanda.

In fact, all that really hung in the balance was a grade, since the trial was being conducted by a class of sophomores from the Facing History School, a small high school on West 50th Street in Manhattan.

Nevertheless, some students were quite invested in the outcome, having spent three weeks preparing in a humanities class that had focused all semester on the epitome of inhumanity: genocide.

The genocide project was very much in line with the school’s mission, which is to graduate students who are prepared to actively participate in a democratic society. The emphasis on civic engagement becomes all the more clear when you look at how the trial fits into the class, which is tightly woven into the curriculum of the school -- itself the product of a civic-minded innovation in New York City public schools that emerged a decade ago.

The New Century High Schools initiative was started in September 2002 by New Visions for Public Schools (in partnership with contributors and the Education Department). The aim was to create a new kind of high school, explained Timothy Farrell, New Vision’s director of communications, by forming partnerships between small schools and various community and education organizations. “These organizations have an interest in seeing students succeed,” he said.

Twelve of these schools were opened in 2002, and after the initiative’s sixth and final year, the total was 99. One was the Facing History School, co-founded in 2005 by its main partner, Facing History and Ourselves, an educational nonprofit organization that trains teachers to engage students actively in their own education and communities.

By studying instances of genocide and racism and applying the lessons of history to their own lives, students learn the importance of ethical decision-making.

Though the organization had never put together a school, the idea was to take what it had been offering teachers on the classroom level (since 1976) and extend that to the whole culture of the school and the community it serves.

“Facing History School was envisioned and currently functions as a laboratory for what Facing History and Ourselves can look like at its peak,” said the organization’s liaison to the school, Daniel Braunfeld, 30, a former teacher at the school (and a juror at the Bronx trial).

The mock trial is a good example of the room for creativity the school’s curriculum allows for, Mr. Braunfeld said, with the aim of “getting kids to wrestle with historical events and documents, pulling them apart and understanding the choices that were made.”

One week before the trial, that is precisely what students in the 10th grade humanities class were busy doing. The prosecution and defense teams were preparing their witnesses for cross-examinations (using the actual judgment and sentence as source material), while the teacher, David Sherrin, 32, who has taught at the school for five years, met with them individually.

“Human rights and justice are the core of the class,” Mr. Sherrin said. The focus of the trial, he added, is “to have students question how and if justice can be achieved after an atrocity like genocide.”

Shakina Kirtan, 15, a prosecutor, who said she aspired to be a lawyer, had an answer: “The perpetrator of a genocide should be punished,” she said. “I’m ready for a good fight.”

But Jermaine Atkins, 16, who said he chose the role of Bizimungu because he liked the center stage, was more wary. “There’s always two sides to a story,” he said -- though he did concede the general was “a bad guy.”

To enhance the unit on the Rwandan genocide, the school turned to one of its 13 partner organizations, the News Literacy Project, which sends journalists to classrooms to teach children how to be smarter media consumers.

Dina Temple-Raston of NPR came in to discuss her book about the news media’s role in the genocide and to interview a Tutsi survivor on Skype, with the class taking part.

“That helped make some of this come alive and got the kids excited about it,” Mr. Sherrin said. So when it came time to start working on the trial, the class was well-versed in the history and ready for deeper engagement.

After impassioned opening statements made before a jury of eight, the lawyers cross-examined 10 witnesses, intent on proving Bizimungu’s innocence or guilt, with painstaking attention to the actual details of the case. The testimony went on for 90 minutes and included some heated exchanges as well as laughter.

Then the lawyers delivered their closing statements, and the jury left the room with the prosecutor Shakina Kirtan’s parting words hanging in the air:

“Will you look at the evidence and see the truth or let the cries of thousands of victims go unanswered?”

After the jury announced its verdict -- guilty of genocide but not of conspiracy to commit it -- Mr. Sherrin led a debriefing discussion, asking the class if justice had been served.

Ivan Severo, the other prosecutor, who was flush with victory, captured the mood in the room when he said, “I feel satisfied with the outcome of our work.”