The London Fire Department is calling a fire Sunday morning suspicious.
Firefighters were called just before 8 a.m. to a vacant building at the intersection of South Street and Maitland Street.
The exterior was on fire and inspector was requested.
Fire crews were able to quickly knockdown the blaze.
At around 9:20 a.m. firefighters left but police and inspectors remained on the scene to determine the cause.
Information on the cause of the fire was not immediately available.