The Justice Department inspector general’s office said Thursday that it was opening an investigation into FBI director James Comey’s decision to inform Congress in a letter that the agency was looking at newly found emails related to Hillary Clinton’s private server. The emails quickly proved irrelevant, but Clinton has said the move, which renewed scrutiny of her email practices days before the election, was a key factor in her narrow loss to President-elect Donald Trump. The inspector general’s office said it was launching the inquiry in response to complaints from the public and lawmakers that the FBI and the Justice Department made politically motivated decisions about the Clinton email investigation during the campaign.