WASHINGTON (AP) — If your job is protecting the first lady's motorcade, mouthing off about the boss can lead to more than a citation in a personnel file.

A District of Columbia police officer found that out this week when he came under investigation for threatening comments he was accused of making about first lady Michelle Obama, though there are conflicting reports about what was said, Police Chief Cathy Lanier said in an email Friday. She did not elaborate.

Police have not revealed what the officer, assigned to a unit that provides a motor escort for the White House and other dignitaries, is accused of saying, and it's not clear how seriously the remarks were meant to be taken. The department and the U.S. Secret Service are investigating what a police spokeswoman called "inappropriate comments." While the Secret Service investigates threats against the first family as a matter of routine, the comments no doubt take on added seriousness given the officer's role within the department.