The fire marshal is investigating another suspicious fire in Sydney.

Firefighters were first called to the abandoned Cornwallis School at around 7 p.m. There was a flare up again at 1:30 a.m. Friday but firefighters, who remained at the scene, were able to contain and extinguish the fire.

The building was being redeveloped as a 16-unit seniors' complex. The developer says he is unsure what is going to happen now.

Police received reports that a young couple was seen near the school.

Security guards have been protecting Cornwallis School until the fire marshal finishes the investigation.

The marks the seventh suspicious fire in the Cape Breton Regional Municipality in the last few weeks.