A lawyer and law professor says the FBI director did a bad and possibly illegal thing.

The F.B.I. is currently investigating the hacking of Americans’ computers by foreign governments. Russia is a prime suspect.

Imagine a possible connection between a candidate for president in the United States and the Russian computer hacking. Imagine the candidate has business dealings in Russia, and has publicly encouraged the Russians to hack the email of his opponent and her associates.

It would not be surprising for the F.B.I. to include this candidate and his campaign staff in its confidential investigation of Russian computer hacking.

But it would be highly improper, and an abuse of power, for the F.B.I. to conduct such an investigation in the public eye, particularly on the eve of the election. It would be an abuse of power for the director of the F.B.I., absent compelling circumstances, to notify members of Congress from the party opposing the candidate that the candidate or his associates were under investigation. It would be an abuse of power if F.B.I. agents went so far as to obtain a search warrant and raid the candidate’s office tower, hauling out boxes of documents and computers in front of television cameras.

The F.B.I.’s job is to investigate, not to influence the outcome of an election.

Such acts could also be prohibited under the Hatch Act, which bars the use of an official position to influence an election. That is why the F.B.I. presumably would keep those aspects of an investigation confidential until after the election.

And that is why, on Saturday, I filed a complaint against the F.B.I. with the Office of Special Counsel, which investigates Hatch Act violations, and with the Office of Government Ethics. I have spent much of my career working on government ethics and lawyers’ ethics, including two and a half years as the chief White House ethics lawyer for President George W. Bush, and I never thought that the F.B.I. could be dragged into a political circus surrounding one of its investigations. Until this week.

By way of full disclosure he tells us what candidates he has supported in this election process – three Republicans and then Clinton.

On Friday, the director of the F.B.I., James B. Comey, sent to members of Congress a letter updating them on developments in the agency’s investigation of Mrs. Clinton’s emails, an investigation which supposedly was closed months ago. This letter, which was quickly posted on the internet, made highly unusual public statements about an F.B.I. investigation concerning a candidate in the election. The letter was sent in violation of a longstanding Justice Department policy of not discussing specifics about pending investigations with others, including members of Congress. According to some news reports on Saturday, the letter was sent before the F.B.I. had even obtained the search warrant that it needed to look at the newly discovered emails. And it was sent days before the election, at a time when many Americans are already voting.

This clarifies, for me at least, how extraordinary and reprehensible Comey’s action was.