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DARBY, Pa. (CBS) — A police chief has harsh words for a school principal after an armed man is allowed to enter a Delaware County elementary school on Friday. Darby Borough Police say 21-year-old Nazher Sabree, of Philadelphia, was arrested after a violent struggle after he was allowed entrance into Park Lane Elementary School by someone who works at the school.

Police say Sabree was walking around the school without a shirt around 9 a.m. A school employee recognized the 21-year-old as a former student and let him into the building.

“At this time, we do not have a statement from that employee as to why the young man was permitted entrance,” school officials said in a statement.

He told school officials he was looking for his bag.

“Dr. Watson-Bouie asked the young man why he was there and he replied that he was looking for a bag and wanted to know if anyone brought it into the building.  Dr. Watson-Bouie stated she would make an all-call to ask if anyone had found the bag. She then escorted the young man out into the lobby and past the secured doors where he could not get entrance back into the main office or the rest of the building. At no time is there any evidence of a gun or signs of violence evident to staff or in the video surveillance,” school officials said.

The principal was eventually able to get Sabree out of the building, but things only escalated.

The situation lasted for three hours before the principal contacted police around 12 p.m.

Police pursued the suspect and it took four officers to bring the 21-year-old down behind the school.

Police say Sabree did threaten officers with his semi-automatic handgun, however, no shots were fired and he was taken into custody.

“The young man was sighted earlier by our School Security Officer walking around picking up bags. The Security Officer noticed the young man was talking to someone in a Verizon Fios van and believed the young man was one of the Verizon workers,” the school says.

Officials are questioning why school staff members did not call police sooner.

Toby Brown said she learned about the situation on the news.

“I should have been told when it happened after everything was calmed down. All the parents should have been notified. To give me the choice to come pick up my kid. I didn’t have a choice to come pick up my kid because I wasn’t informed,” said Brown.

Darby Borough Police Chief Robert Smythe was visibly upset and has called for the principal to be removed from the job for the way the situation was handled.

“How many school shootings are done in this day and age that we don’t know what’s going on, but once the gun gets inside of the building and that gun is fired, people are hurt, and at this point it could’ve been the children at Park Lane School and I personally hold that principal accountable for what happened today,” said Smythe.

Smythe says the school did go into lockdown at some point.

No children were hurt during the incident.

Some are questioning why Dr. Watson-Bouie did not push the Panic Button which alerts all local police agencies that there is an armed intruder in the building.

The school says, “It was not utilized as Dr. Watson Bouie had no evidence that there was an armed intruder.”

The school district will continue to investigate this incident.