London fire officials say an explosion may have caused a blaze that critically injured one person at a northeast-end apartment.
Firefighters were called to the high-rise at 756 Kipps Lane near Adelaide Street North around 4:40 p.m. on Monday.
Crews were able to extinguish the flames within half an hour and residents were allowed to return to their units.
One person suffered life-threatening injuries and was taken to hospital. As of Tuesday, that individual remained in critical condition.
Early indications are the blaze was sparked by a possible explosion.
"The fire was deemed to be suspicious in nature and the investigation was assigned to members of the Major Crime Section, in conjunction with the London Fire Department Inspector and Office of the Fire Marshal," London police said.
Investigators were expected to be back on scene throughout the day Tuesday.
Anyone with information about this fire are asked to call police at 519-661-5670 or Crime Stoppers at 1-800-222-TIPS (8477).