In another development, police have also taken at least five suspects into custody. They say the five are suspects in a robbery investigation, but will not say if they are the males being sought for the armed robbery at the high school.
On Thursday afternoon, four male suspects robbed three students of their cellphones at gunpoint at Etobicoke's Thistletown Collegiate Institute before fleeing the scene in a stolen car, Toronto police said.
Shortly after noon, the four — dressed in black, hooded sweatshirts and some wearing masks — entered Thistletown Collegiate and robbed two female students and attempted to rob a male student, Supt. Ron Taverner told reporters Thursday.
As the male student fled, one of the suspects chased him and fired a shot at him in the parking lot, but missed, he added.
The four suspects, believed to be in their early 20s, then fled the scene in a 2006 Toyota Blue four-door vehicle, which was believed to be stolen two days ago.
A vehicle matching that description was seized Thursday evening.
Taverner said that there was no indication that the suspects were students.
"This is very disturbing," he told reporters. "It appears to be a total random act, a violent act, that could have been much, much worse than it turned out. But my goodness, it's terrible."
Police say one gun was involved.
The school was placed under lockdown after police said they were engaged in a "robbery with gun investigation." It has since been lifted.
Shortly after 2 p.m., Const. Ryan Willmer tweeted that a "search had been completed" inside the school and that "students will be escorted out shortly."
The high school is located at 20 Fordwich Crescent., near Islington Avenue and Elmhurst Drive.