A wind farm near the village of Aghios Vassilios, believed to have triggered the massive wildfire burning west of Athens for a fourth day Monday, is also suspected of having caused a blaze that was quickly contained a few weeks ago – shortly after the farm started operations.

Fire Service investigators have faulted sparks falling from the overhead power line linking the wind farm of five turbines with the main grid as having started the massive fire that has destroyed more than 10,000 hectares of forest and scrub. Two people died Sunday when two firefighting helicopters helping contain the blaze collided in mid-air.

Authorities arrested the electrical engineer who was responsible for the power lines, as well as the mayor of the town of Stylida in central Greece, Ioannis Apostolou, whose construction company built the network. The wind farm owner also faces charges.

Fire Service investigators also suspect that the same power lines started a much smaller fire in the area on June 27, which was extinguished after destroying just six hectares.

At the time, the fire was blamed on sparks falling from the power lines after two cables came into contact and caused a short circuit. Nobody had been arrested at the time, and the incident apparently led to repairs being carried out on the line by Apostolou’s firm.