(Reuters) - A quick-moving early morning fire that killed seven people in an apartment building in the Canadian city of Montreal in March was deliberately set, police said on Monday.
Police said traces of accelerant had been found in a part of the building, which was located in the city center. Another nine people were injured in the blaze.
"(An) accidental cause has been ruled out. We are now talking about a criminal investigation ... the major crimes division and arson squad are working closely," Montreal police service inspector David Shane told a press conference.
He declined to give more details. Three of the victims rented their apartments through AirBnb, relatives told the Canadian Broadcasting Corp.
The CBC, citing an independent watchdog, said more than 90% of short-term rental units listed on Airbnb in Montreal - the largest city in the province of Quebec - did not have permission to operate.
In the wake of the disaster, AirBnb said it would remove all Quebec listings that had not been authorized by the provincial government. AirBnb was not immediately available for comment on the police's comments.
(Reporting by David Ljunggren; Editing by Sandra Maler)