Greek: "ὁ γὰρ πρότερον ἐὼν αὐτόθι αὐτόματος κατεκάη"
(http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%...)
Literal translation: "because the one [= the temple] that previously existed in the same place completely burned down on its own"
The crux here is on "αὐτόματος", for which see LSJ: http://www.perseus.tufts.edu/hopper/morph?l=au%29to%2Fmatos&...