NEW YORK (CBSNewYork) — The disturbing case of the death of a student in a New York City school last year has taken a strange new twist.

As WCBS 880’s Mike Sugerman reported, the question has become what did the Urban Assembly School for Wildlife Conservation know, and when did it know it?

“The Department of Education has blood on its hands,” said attorney Sandy Rubenstein.

Rubenstein represents the mother of Matthew McCree, 15, who was stabbed to death at the school last year while a second student was stabbed and injured. Another student, Abel Cedeno, was charged.

Cedeno claims he snapped after being taunted for his sexuality, but the victim’s mother said the school was warned three year ago that Cedeno had knives in his backpack and pulled them on his own family.

The attorney said someone leaked a memo from the school.

“The Department of Education had notice of a serious problem and did nothing,” Rubenstein said.

There was no comment late Wednesday from the Department of Education.