NEOS VOUTZAS, Greece — The first fire alarm sounded in Kineta, a town an hour west of Athens, the capital, at 12:30 p.m. on Monday. Then, at 4:57 p.m., the authorities received calls on their 199 hotline reporting flames near Rafina, east of the capital.

Just about an hour later, the wildfire had reached Neos Voutzas, to the northeast, and then, powered by gale-force winds, it moved “like a lava flow” down the hill to the seaside town of Mati, fire officials said.

Greeks on Wednesday were still piecing together one of the nation’s worst disasters in recent memory. But many were asking how so many scattered fires had broken out in so short a span and spread with such fatal velocity. Suspicion of arson combined with grief and recrimination as shattered Greeks sifted through the ruins of fires that killed at least 81 people.