Sorting through the wreckage from the affair that cost CIA Director David Petraeus his job and four-star reputation late last week will no doubt turn up details worthy of a trashy novel.

That's regrettable, especially for the wives, husbands and children who were innocently dragged into this mess by those they loved and trusted. Too often trysts involving public figures who are also consenting adults get more attention than they deserve.

Not this time, though. A thorough public reconstruction of events is necessary to maintain the nation's faith in its intelligence and law enforcement communities and their leadership in the wake of the scandal. We need to know more about who knew what and when they knew it to comment in detail on where mistakes might have been made in the FBI's handling of the original investigation.

There may be legitimate reasons why news of the Petraeus affair hit Sen. Dianne Feinstein, chairman of the Senate Intelligence Committee, like a "lightning bolt" when reporters contacted her about the investigation on Friday, only hours before news broke that Petraeus had resigned. But the nation needs to hear that explanation, as well as why news of the monthslong probe moved so slowly up the chain of command as the presidential election approached, only reaching the White House on Election Day.

It appears the investigation began in early summer when a Florida woman, Jill Kelley, approached the FBI's Tampa office with harassing e-mails that accused her of seeking an intimate relationship with Petraeus. According to the Wall Street Journal, it took agents weeks to link the e-mails to Petraeus biographer Paula Broadwell and to determine that the writer was having an extramarital affair with the retired military hero.

Agents initially were concerned that Broadwell might have breached national security, an unnamed source told the Washington Post this weekend, which could explain why the FBI kept the investigation so quiet for so long. Policies prohibit FBI and Justice Department officials from revealing details of ongoing criminal inquiries. But at the same time the agencies have a responsibility to inform congressional intelligence committees of significant national-security issues.

Feinstein, a California Democrat, and New York Rep. Peter King, the Republican chairman of the House Homeland Security Committee, both want answers. Their bipartisan skepticism about the investigation's scope and timeline is understandable. They deserve a full accounting, and so do the American people.