When Was Moody Captured

When was Moody switched?

According to Wikia, this happened late on August 31st of Year 4, or September 1 – before the first day of school. Here’s Barty’s Veritacerum confession from Goblet of Fire, showing that the impersonation started right when Moody was captured: “You needed Alastor Moody,” said Dumbledore.

When did Dumbledore suspect Moody?

At the end of GOF when fake Moody takes Harry to his office after he returns from the maze, Dumbledore eventually comes in and stuns him. He knows it is an impostor, but before he changes back to Barty Crouch Jr. he tells McGonagall to get Winky from the kitchens.