The Kitchener fire department says its investigation of the condo fires on Louisa Street is expected to be complete later Wednesday.
Chief Fire Prevention Officer Tom Ruggle said he could not comment on what the cause of the fire was, or whether or not it is being considered suspicious. The Ontario Fire Marshal is also investigating the blaze.
"Once the fire marshal's done on the site, we'll be able to give you an idea of what has transpired and what the next steps are," said Ruggle.
Ruggle added there was a flare up in one of the units late Tuesday evening, but it was quickly contained by fire crews safeguarding the site.
The fire department says it will be providing more information to the public Thursday morning.