Story highlights Paul Callan says that the FBI director, by foolishly making a public announcement that the agency is reviewing newly discovered emails related to Hillary Clinton's personal server, has inserted himself yet again into the campaign

He says his clumsy handling of the probe is reason for Comey to resign

Paul Callan is a CNN legal analyst, a former NYC homicide prosecutor and currently is "of counsel" to the New York law firm of Edelman and Edelman, PC, focusing on wrongful conviction and civil rights cases. Follow him @paulcallan

(CNN) Donald Trump's oft-repeated claim that the FBI's investigation of "Crooked Hillary" and the presidential election itself were and are "rigged," seems to have thrown FBI Director James Comey into a state of panic. In foolishly making a public announcement that the bureau is reviewing newly discovered emails related to Hillary Clinton's personal server, he has inserted himself yet again into the presidential campaign.

The FBI virtually never announces the commencement or termination of ongoing criminal investigations or the discovery of new evidence. Such inquiries are often conducted in relative secrecy, enabling a more efficient investigation.

It is not unusual for investigations in so-called "white collar" cases to go on for years, luring the target into an unfounded belief that he or she is in the clear. Then the hammer falls. A grand jury indictment is announced by the Department of Justice and the handcuffs are swiftly employed.

The old, sensible FBI rule book apparently has been thrown on the trash heap this year. While undoubtedly attempting to be open and "transparent," to protect the reputation of the FBI, the FBI director has tossed a Molotov cocktail into the presidential race.

The FBI was now taking "appropriate investigative steps. ... to assess their importance to our investigation." What in the world does this mean? One thing it means is that this issue will move to front and center during the final days of the presidential campaign.

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