". . . Muggle neighbors heard bangs and shouting, so they went and called those what-d’you-call-’ems - please-men. Arthur, you’ve got to get over there --"
-- Amos Diggory's head in the Weasley fire (GF11)
At the time, this event was blamed on Mad-Eye being paranoid and overly defensive, blasting away at things when he felt like he was under attack. The Ministry never assumed that this was genuine:
“Arthur, you know Mad-Eye … Someone creeping into his yard in the dead of night? More likely there’s a very shell-shocked cat wandering around somewhere, covered in potato peelings. But if the Improper Use of Magic lot get their hands on Mad-Eye, he’s had it — think of his record — we’ve got to get him off on a minor charge, something in your department — what are exploding dustbins worth?” (GF11)
But in fact it was a very real attack. Moody had been attacked, subdued, and trapped in a magical trunk while Barty Crouch Jr. took his place as a teacher at Hogwarts.