Five people, including a child, were taken to hospital after a fire in Richmond Hill Monday morning and are in critical condition, fire officials say.
York Regional Police say they were called after 3 a.m. to a home near Skywood Drive and Rollinghill Road.
Paramedics say they assessed all five patients, four of whom lacked vital signs.
Four of them were rescued from within the house and one managed to escape, according to Jim Kettles from the Office of the Fire Marshal.
Police are investigating the fire alongside them after suspicious items were found at a school nearby, Kettles said.
"We're going to devote every resource that we need to hopefully uncover what it was that happened here," he told reporters at the scene.
A gas can and a backpack were found at Saint Marguerite d'Youville Catholic School, leaving many nearby residents like Clair Tang in disbelief.
"I can't believe that somebody can do this to our neighbors," she said.
Police are yet to make any arrests in connection with the fire.