A city teen will remain behind bars without bail after being arraigned Thursday on charges he fatally stabbed a fellow classmate and seriously wounded another inside their Bronx high school a day prior.

Abel Cendeño, 18, appeared before a judge at the Bronx criminal courthouse.

He faces a slew of charges including second degree murder, attempted murder, manslaughter, assault and criminal possession of a weapon.

Police say the attack spurred from a heated argument during a third period history class Wednesday at PS 67 Mohegan School/Urban Assembly School for Wildlife Conservation in East Tremont.

Investigators say Matthew McCree, 15, was killed after being stabbed in the chest with a three-inch spring-loaded switchblade.

Arian Laboy, 16, was also stabbed and rushed to the hospital, where he remains in critical condition.

Officers say they recovered the weapon at the scene.

While in court, prosecutors requested an order of protection be issued for Laboy.

As the judge read the rules of the order in court Thursday Cendeño repeatedly said, "Yes I understand your honor."

Savannah Hornback, a family friend who was at court, tells NY1 Cendeño was a good kid and that it was the result of him being bullied for years. She says his mother had gone to the school several times to complain about it but nothing was done.

"The main concern of the family right now is you know and we're in no way trying to lessen Abel's involvement in it but this was an extreme case of bullying and the family does send their condolences and sympathies to the victims' families as well," Hornback said.

Cendeño's lawyer requested her client receive medical attention, be put on suicide watch and undergo a psychiatric evaluation.

Meanwhile, students at PS 67, which houses both an elementary and high school, returned Thursday morning with added security measures in place.

Metal detectors and X-ray scanners were brought in and grief counselors have been assigned to the site.

A PS 67 student who spoke with NY1 says the new safety measures are long overdue.

"It's not the first time somebody has brought a knife to school. This has happened before and they said they are determined that there shouldn't be the detectors because they don't want to make it feel like a prison, but really I think this school needs it more than any other school," said the student.

Mayor Bill de Blasio says this is the first time in decades that a student has been killed in one of the city's public schools.