Investigators say a massive fire that destroyed an iconic downtown Nanaimo heritage building last month was sparked by an electrical failure.

No one was injured in the March 30 blaze, which levelled 15 businesses and suites in the old Jean Burns building on Commercial Street.

Fire officials say the investigation into the incident is complete and the cause was determined to be electrical in nature, originating in a void space between the first and second floors in the centre of the building.

But a power disruption that occurred in the area on the afternoon of the fire wasn’t a contributing factor, investigators say.

The fire has been classified as accidental, and the building is expected to be a write-off.