Greek authorities have charged seven people with starting a number of forest fires that have so far claimed 63 lives.
Anti-terrorist authorities said they were joining the investigation, and it is thought one possible motive could be that unscrupulous property developers were hoping to move in on the areas where forest has been destroyed.
This comes as firefighters backed by an international force battled the flames for a fifth day.
Meanwhile, Greek opposition MPs have attacked the government's response to the devastating fires.
In the capital, Athens, hundreds of people took to the streets in protest, many blaming the government.
