Sudbury firefighters responded to a suspicious fire Wednesday night at a residential unit on Laforest Street and now police have taken over the investigation.

Fortunately, everyone was evacuated safely and no one was hurt and now police are looking for the person who deliberately set the fire.

"Right now, the investigation is ongoing. The determination is where the fire started, how it started and why it started," said Kaitlyn Dunn of the Greater Sudbury Police Service. "Right now officers, detectives are canvassing the area and holding the scene in order to conduct a search warrant on the unit."

Three units housing five people had to be evacuated Wednesday night and the property owner put the tenants up in a local hotel.

"It was started in an apartment unit that was suspected to have been vacated and empty, and so with those concerns and information that they had gathered, certainly we contacted our partners at the Greater Sudbury Police Service and the Ontario Fire Marshals Office who have taken over this as an investigation," said Jesse Oshell, the Greater Sudbury Fire Service Deputy fire chief.

Some tenants were able to return to their units on Thursday with police still securing the basement unit.

"Due to the suspicious circumstances, we are investigating this as an arson. We believe it to be a targeted and isolated incident and we do not believe that there is any threat to the public," Dunn said.

The property manager at the residential unit told CTV News there was a squatter staying in the basement unit and they were working with the Landlord and Tenant Board to evict.