NEW YORK (CBSNewYork) — The deadly stabbing at a school in the Bronx was the first homicide inside a New York City school in 25 years.

It’s raising concerns about school safety and anti-bullying efforts.

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The Department of Education refused to confirm multiple reports about a bullying angle to the incident, but moved quickly to reassure parents that school will be safe when classes resume on Thursday.

Signs in New York City schools serve notice — visitors are subject to ‘unannounced scanning.’

The NYPD plans to do just that on Thursday, at the Bronx school that became a crime scene.

“Tomorrow will entail the machines as well as hand wands, and we’ll continue on a day-by-day to determine overall need,” Mark Rampersant, Deputy Chief Executive, School Safety said.

For parents the need is obvious.

“De Blasio, you need to do something about these metal detectors in school with these kids,” one parent said.

The mayor said the city was working to ensure their safety.

“We will use every measure to make sure every child is safe,” the mayor said.

As CBS2’s Tony Aiello reported, with two assaults last year, the school did not meet the threshold for daily metal detectors.

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But there was a red flag.

In the annual school survey when asked if ‘order and discipline are maintained at the school’ 81 percent of teachers disagreed.

The deputy chancellor said that prompted extra help from the central office.

“The Field Support Center has done a lot of support for this school. They’ve had staff trained in de-escalation techniques, in therapeutic crisis intervention,” deputy chancellor Elizabeth Rose said.

Crisis came, and it was deadly.

Some students say accused killer Abel Cedeno was subjected to bullying.

“Not physically, you know, verbally. I guess they thought they were funny,” Asia Johnson said.

Parents want answers; what did the DOE know, and what did it do?

“Had they moved him to another location, had they moved the other children to another location. Somebody could have done something. It’s saddening. It could have been prevented,” one parent said.

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Chancellor Farina said wait for the investigation to wrap up before blaming bullying. With so many questions surrounding the case, the mayor has four public events on Thursday, but no scheduled Q and As with reporters.