A teenager charged in the stabbing death of a classmate in a Bronx school pleaded not guilty Wednesday. NY1's Lindsay Tuchman filed the following report.

Abel Cedeno, 18, pleaded not guilty Wednesday to manslaughter.

He is accused of fatally stabbing Matthew McCree, 15, and critically wounding another student in a classroom at the Urban Assembly School for Wildlife Conservation in the Bronx in late-September.

Cedeno's lawyers said persistent bullying was responsible for the attack.

"This incident occurred not because of some disease and defect with Mr. Cedeno, but because of the disease and defect in that school," defense attorney Christopher Lynn said in the courtroom.

On Wednesday, the education department confirmed that about 30 students have transferred from the school since the stabbing.

Schools Chancellor Carmen Farina has also removed the principal to ensure "a more inclusive learning environment."

An action that McCree's friends and family call too little, too late.

"The responsibility for this wrongful death lies with the defendant in this case and the department of education," said Sanford Rubenstein, an attorney for McCree's family.

This was Cedeno's first court appearance, as he skipped an earlier date, partly to diffuse tensions in the courtroom.

The victim's mother said it was emotional finally seeing him.

She and other relatives and friends of McCree gathered outside the Bronx courthouse after the arraignment, chanting "Justice for Matthew."

"I was angry, I was pissed because he has his life. He's 18, he lived past 15, and he's going to live many more lives, and my son only made it to 15 thanks to him," Louna Dennis said.

Cedeno's mother, who was in Puerto Rico at the time of the attack, says her son is staying strong in jail.

"It's real hard, real, real hard. It's incredible what happened to my kids, my son. Nobody helped us. I tried to get so many times to school and get some help, and they ignored us," Luz Hernandez said. "'Be a better person' — that's what they said to my son. 'Ignore and be a better person.'"

Cedeno is due back in court Nov. 29.