The students began exiting C.W. Jefferys Collegiate Institute and boarding Toronto transit buses shortly before 6 p.m., but police Chief Bill Blair said they would be brought to another nearby school before they would be free to go home.
The shooting at the north Toronto school occurred around 2:30 p.m. Officers received a call about a possible drowning, but arrived at the school to find a teenage boy in a corridor suffering from a single gunshot wound, prompting the lockdown.
Blair held a news conference outside the school at 5 p.m. - while the students were still locked down - and offered assurances to worried parents, saying officers had secured the school and were "on every floor and in every room."
He appealed to students to remain calm.
Blair indicated the victim was rushed to hospital in grave condition but later died.
"A young man lost his life, a young student lost his life in the school," he said.
"Students have a right to a safe school environment. It is shocking that such a crime could take place in our schools."
Friends of the victim identified him as Grade 9 student Jordan Manners.
Police didn't comment on a suspect, but said it was not a situation in which a gunman roamed the halls.
"I have no information at the present time with respect to suspects," Blair said. "The only information we have is that this young man was found with a single gunshot wound and that he was transported to hospital."
As word of the shooting spread through the neighbourhood, frantic parents - many in tears - rushed to the school, hoping their child wasn't involved.
"I was thinking that it could be my son," one woman said.
"You're pretty scared," another mother said.
Ontario Premier Dalton McGuinty offered his condolences to the families and friends of the victim.
"I also know I speak for all Ontarians when I condemn and deplore the violence we've seen here today," McGuinty said in a statement. "I want the entire community at C.W. Jefferys C.I. to know that they are in my thoughts and prayers at this difficult time."
Yellow police tape surrounded the school, and outside the barrier, police vehicles and curious onlookers - including many parents of students - jammed the streets.
Some parents were able to reach their children inside the school on cellphones.
The school is located near the Jane-Finch corridor, a poor area of Toronto noted for years for its high crime rate.
Police said no weapon had been found by early Wednesday evening.
The Toronto District School Board's website said the school has about 850 students.
The shooting comes a little more than a month after a gunman killed 32 people at Virginia Tech before taking his own life.
In September, a gunman at Montreal's Dawson College killed a student and wounded 20 others before he died from police gunfire.
P.S. this was in my school! i was in a lock down for 6 hours! i feel soo sorry for Jordan😭😭
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