How the BBC is reporting this here may be of some interest, that they (the fires) seem to have spread into Athens now as the city is descibed as being covered with smoke and some of the suburbs seem to be at risk.
It must be quite be quite aweful as Athens is in a bit of a bowl and I know the city when traffic pollution is bad. I got caught in a riot there and the CS gas took over a day to clear in the tight windless and airless streets.
What is being reported here is that the Grrek Prime Minister is alluding to dark forces who have been at work particularly in the Athenian suburbs where the Fire Brigade is not due to fighting fires elsewhere. One presumes he is alluding to the future elections.
Also that a male has been arrested and charged in the western Peloponese with arson and multiple homicides (at least six), you are also under a state of emergency.
As Paul quite rightly says there are no doubt multiple reasons for these fires and it probably depends whether you are a politician, a land owner, a householder or a political activist as to the reasons. Whatever way it is a tragedy of truly Greek and epic proportions.