The largest residential fire in Kitchener's history, which gutted huge portions of the Victoria Common condominium and townhouse complex, is now being investigated as a possible arson, say police.

The fire started early Tuesday morning at the complex at the corner of Louisa and St. Leger Streets and caused $5 million in damage by the time it was extinguished.

‚ÄčThe Ontario Fire Marshal wrapped up their investigation on Wednesday night, and referred the case to the Waterloo Regional police, said Tom Ruggle, the Kitchener fire department's Chief Fire Prevention Officer.

"At this time based on the findings of the fire marshal's office, it's being referred to the Waterloo Regional police as having indicators of being suspicious in nature," he said. 

Tom Ruggle Kitchener Fire

Tom Ruggle, the Kitchener fire department's Chief Fire Prevention Officer, stands in front of the Victoria Common housing complex at the corner of Louisa and St. Leger streets. A fire caused $5 million in damage on Tuesday morning, one that Ruggle said was the biggest residential fire in Kitchener's history. (Amanda Grant/CBC)

Ruggle wouldn't elaborate on what those indicators were. 

"When indicators are found that are not explainable by the circumstances, what we'll usually do is transfer that to the police for further follow-up," he said. 

Police spokesperson Olaf Heinzel said evidence at the scene suggests the fire may have been deliberately set, but like Ruggle, he wouldn't go into specifics. 

"We can't talk about what evidence or information we may now have," he said. "That would potentially jeopardize what we're doing."

The fire began before 5:30 a.m. in the block of townhouse units that were under construction. 

William Liske, the general counsel for the Losani Homes, the builder of the complex, called the damage "catastrophic."

Late Tuesday night, there was a flareup of flames in one of the units, but it was quickly doused by fire crews watching over the site. 

No one was injured in the fire.