Sources tell CBC News a man in his 50s who is facing charges after allegedly bringing an air gun into a public elementary school has ties to the school.

The call came in to police at about 10:35 a.m. ET Thursday from D. Roy Kennedy Public School, a JK-8 school at 919 Woodroffe Ave., between Carling Avenue and Highway 417.

Police said Thursday the suspect walked inside with what appeared to be a firearm, pulled the fire alarm and then went to the principal's office.

Responding officers arrived within minutes and used a Taser on the man. He was taken to hospital to be assessed, police said. No one else was hurt.

On Friday the man remained at hospital for a 72-hour mental health assessment, police said, and charges against him are pending.

Children at the school were taken to nearby St. Paul's Presbyterian Church as a precaution. Due to the investigation, the students weren't allowed back inside the school Thursday.

No buzz-in system for school's doors

D. Roy Kennedy's doors are left open during the school day, with no buzz-in system for visitors.

Walter Piovesan, the Ottawa-Carleton District School Board's assistant director of education, said it's up to individual schools if they want to install such a system.

"The buzzer system isn't foolproof," he said. "It goes to what kind of environment you want to create, is it a welcome environment?

Brett Reynolds, who works on safety with the English public board, said D. Roy Kennedy does have a sign-in policy for guests and locks every door except for the main one.

He said there has been money available if schools decide to install a buzz-in system.

Piovesan said the board will review its policy on such systems.

Of the 125 elementary schools in the OCDSB, 59 have added safety features, which includes at least a buzz-in system.