Investigators say a fire that ripped through half a duplex and damaged two other homes on Regent Drive in Dartmouth Sunday started on a wooden deck behind the property.

"Most of the fire started outside and that's why the fire spread so rapidly," said Roy Hollett, deputy fire chief with Halifax Fire.

Hollett says he expects to have a final report on the incident Tuesday morning. The fire department is not yet citing a cause for the blaze.

Investigators following up

"The investigators are still doing the last pieces of the followup and that's interviewing and talking to people in the area and what they can pass on about what was on the deck — if there was a barbecue, if there were ash trays, they're just looking for what could be there that could have contributed to a fire," he said.

Three homes were damaged in the Sunday evening fire. One half of a duplex is the most severely damaged and is not liveable.

The other half of the duplex has "minimal" smoke and water damage and is liveable. A blue house next to the duplex was burned on the side.

With files from Shaina Luck