CIA Director David Petraeus and Paula Broadwell, a former military intelligence officer and his biographer, adopted a well-worn online trick, in an apparent attempt to keep their communications secret. 
 
 They wrote their "intimate messages" as draft e-mails in a shared Gmail account, according to the AP, allowing them to see one anothers' messages while leaving a much fainter data trail. When messages are sent and received, both accounts record the transmission as well as such metadata as the IP addresses on either end, something the two seemed to be seeking to avoid. 
 
 Petraeus and Broadwell apparently used a trick, known to terrorists and teen-agers alike, to conceal their email traffic, one of the law enforcement officials said. Rather than transmitting emails to the other's inbox, they composed at least some messages and instead of transmitting them, left them in a draft folder or in an electronic "dropbox," the official said. Then the other person could log onto the same account and read the draft emails there. This avoids creating an email trail that is easier to trace. 
 
 The trick has achieved notoriety as a tactic of terrorists who are rightly wary of espionage. 
 
 It's the sort of measure you take if you fear there's a risk that someone will look in on you. And it's been around for quite some time, which may be why the FBI investigators were not fooled by it. 
 
 A January 2005 PBS special on al-Qaeda identified the tactic as one of several "terrorist tricks," alongside logging in from public Internet cafes. The trick is also used in a 2008 spy film "Traitor." ||||| CIA Director David Petraeus was shocked to learn last summer that his mistress was suspected of sending threatening emails warning another woman to stay away from him, former staff members and friends told The Associated Press. 
 
 FILE - In this Aug. 31, 2011 file photo, former Commander of International Security Assistance Force and U.S. Forces-Afghanistan Gen. Davis Petraeus kisses his wife Holly during an armed forces farewell... (Associated Press) 
 
 In the frame grab from C-SPAN Book TV video taken Feb. 6, 2012, author Paula Broadwell speaks to an audience about the book she co-authored, "All In: The Education of General David Petraeus," at the Politics... (Associated Press) 
 
 Jill Kelley leaves her home Monday, Nov 12, 2012 in Tampa, Fla. Kelley is identified as the woman who allegedly received harassing emails from Gen. David Petraeus' paramour, Paula Broadwell. She serves... (Associated Press) 
 
 FILE - In this Feb. 1, 2009 file photo, Gen. David Petraeus, commander U.S. Central Command, left, stands with his wife Holly before the NFL Super Bowl XLIII football game between the Arizona Cardinals... (Associated Press) 
 
 This July 13, 2011, photo made available on the International Security Assistance Force's Flickr website shows the former Commander of International Security Assistance Force and U.S. Forces-Afghanistan... (Associated Press) 
 
 Petraeus, who led U.S. military efforts in Iraq and Afghanistan, resigned his CIA post Friday, acknowledging his extramarital affair with his biographer-turned-lover and expressing deep regret. The scandal has rocked Washington, where members of Congress demanded to know why a months-long probe that ended the former general's storied career was kept quiet for so long. 
 
 Petraeus told associates his relationship with the second woman, Tampa socialite Jill Kelley, was platonic, though his lover Paula Broadwell apparently saw her as a romantic rival. The retired general also denied to these associates that he had given Broadwell any of the sensitive military information alleged to have been found on her computer, saying anything she had must have been provided by other commanders during her reporting trips to Afghanistan. 
 
 The associates spoke Monday on condition of anonymity because they weren't authorized to publicly discuss the matters, which could be part of an FBI investigation. 
 
 Meanwhile, FBI agents appeared at Broadwell's Charlotte, North Carolina, home Monday night and appeared to be conducting a search. An FBI spokeswoman confirmed the agents' presence but did not say what they were doing. 
 
 New details of the investigation emerged as President Barack Obama hunted for a new CIA director. 
 
 Kelley, the Tampa woman, began receiving harassing emails in May, according to two federal law enforcement officials. They, too, spoke only on condition of anonymity because they were not authorized to speak publicly about the matter. The emails led Kelley to report the matter, eventually triggering the investigation that led Petraeus to resign as head of the intelligence agency. 
 
 FBI agents traced the alleged cyber harassment to Broadwell, the officials said, and discovered she was exchanging intimate messages with a private gmail account. Further investigation revealed the account belonged to Petraeus under an alias. 
 
 Petraeus and Broadwell apparently used a trick, known to terrorists and teenagers alike, to conceal their email traffic, one of the law enforcement officials said. 
 
 Rather than transmitting emails to the other's inbox, they composed at least some messages and instead of transmitting them, left them in a draft folder or in an electronic "dropbox," the official said. Then the other person could log onto the same account and read the draft emails there. This avoids creating an email trail that is easier to trace. 
 
 Broadwell had co-authored a biography titled "All In: The Education of General David Petraeus," published in January. In the preface, she said she had met Petraeus in the spring of 2006 while she was a graduate student at the Kennedy School of Government at Harvard and she ended up following him on multiple trips to Afghanistan as part of her research. 
 
 But the contents of the email exchanges between Petraeus and Broadwell suggested to FBI agents that their relationship was intimate. The FBI concluded relatively quickly _ by late summer at the latest _ that no security breach had occurred, the two senior law enforcement officials said. But the FBI continued its investigation into whether Petraeus had any role in the harassing emails. 
 
 Petraeus, 60, told one former associate he began an affair with Broadwell, 40, a couple of months after he became the director of the CIA late last year. They mutually agreed to end the affair four months ago, but they kept in contact because she was still writing a dissertation on his time commanding U.S. troops overseas, the associate said. 
 
 FBI agents contacted Petraeus, and he was told that sensitive, possibly classified documents related to Afghanistan were found on her computer. He assured investigators they did not come from him, and he mused to his associates that they were probably given to her on her reporting trips to Afghanistan by commanders she visited in the field there. The FBI concluded there was no security breach. 
 
 One associate also said Petraeus believes the documents described past operations and had already been declassified, although they might have still been marked as "secret." Broadwell had high security clearances on her own as part of her job as a reserve Army major working for military intelligence. But those clearances are only in effect when a soldier is on active duty, which she was not at the time she researched the Petraeus biography. 
 
 During a talk last month at the University of Denver, Broadwell caught attention when she said the CIA had detained people at a secret facility in Benghazi, Libya, and the Sept. 11 attack on the U.S. Consulate and CIA base there was an effort to free those prisoners. 
 
 Obama issued an executive order in January 2009 stripping the CIA of its authority to take prisoners. The move meant the CIA was forbidden from operating secret jails across the globe as it had under President George W. Bush. 
 
 CIA spokesman Preston Golson said: "Any suggestion that the agency is still in the detention business is uninformed and baseless." 
 
 Broadwell did not say who told her about CIA activities in Libya. The video of Broadwell's speech was viewed on YouTube. 
 
 A Petraeus associate said the retired general was shocked to find out about Broadwell's emails to Kelley. Petraeus was not shown the messages, but investigators told him the emails told Kelley to stay away from the general in a threatening tone. 
 
 Petraeus told former staffers and friends that he was friends with Kelley and her surgeon husband, Scott, and regularly visited their brick home with imposing white columns overlooking Tampa Bay. 
 
 Jill Kelley, 37, served as a sort of social ambassador for U.S. Central Command, hosting parties for the general when Petraeus was commander there from 2008-2010. 
 
 A photo shows Petraeus and his wife, Holly, with the Kelleys and Jill's identical twin sister Natalie Khawam in the Kelleys' front yard, decked out in party beads with a pirate flag in the background. The sisters _ hard to differentiate in the picture with their matching long dark locks and black dresses _ also competed in a cook-off filmed for a Food Network show called "Food Fight" in 2003. 
 
 Jill Kelley regularly kept in touch with then-Gen. Petraeus when he became commander of the Afghan war effort, the two exchanging near-daily emails and instant messages, two of his former staffers say. But those messages were exchanged in accounts that his aides monitored as part of their duties and were not romantic in tone, the staffers said. 
 
 Kelley did not answer the door at her Tampa home Monday morning, and later left her home by car without talking to reporters. The Kelleys hired Abbe Lowell, a Washington lawyer who has represented well-known clients including lobbyist Jack Abramoff and former presidential candidate John Edwards, and released a statement Sunday through a Washington-based crisis management firm that she and her family had been friends with the Petraeus family for five years and wanted to respect their privacy. 
 
 Petraeus and his family are devastated over the affair, especially Mrs. Petraeus, who "is not exactly pleased right now," after 38 years of marriage, said Steve Boylan, a friend and former Petraeus spokesman who spoke to him over the weekend. 
 
 "Furious would be an understatement," Boylan told ABC television's "Good Morning America." The couple has two adult children, including a son who led an infantry platoon in Afghanistan as an Army lieutenant. 
 
 Broadwell is married with two young sons and lives in Charlotte, North Carolina. She has not returned phone calls or emails seeking comment. 
 
 As the criminal investigation continued into the emails to Kelley, FBI Director Robert Mueller and eventually Attorney General Eric Holder were notified that agents had uncovered what appeared to be an extramarital affair involving Petraeus, said one of the law enforcement officials. 
 
 Broadwell and Petraeus have each been questioned by FBI agents twice in recent weeks, with both acknowledging the affair in separate interviews. The FBI's most recent interviews with Broadwell and with Petraeus both occurred during the week of Oct. 29, days before the election, one of the law enforcement officials said. The FBI notified Obama's director of national intelligence, James Clapper, of the investigation on Tuesday, Nov. 6, Election Day. 
 
 Clapper called Petraeus that night and urged him to resign. Clapper informed the White House late Wednesday, and aides informed the president Thursday morning, before Petraeus came to personally hand in his resignation letter. 
 
 Some members of Congress are questioning why they weren't told sooner. Democratic Sen. Dianne Feinstein of California, who heads the Senate Intelligence Committee, said she wants to investigate why she had to find out from news reports Friday. 
 
 But there were at least a couple of members of Congress who heard inklings of the affair before the election. Republican Rep. Dave Reichert of Washington state received a tip from an FBI source that the CIA director was involved in an affair in late October. Reichert arranged for an associate of his source at the FBI to call House Majority Leader Eric Cantor on Saturday, Oct. 27, according to Cantor spokesman Rory Cooper. 
 
 The FBI agent who contacted Reichert was the same one who first received the allegations from Kelley, a federal law enforcement official said Monday night. That agent's role in the case consisted simply of passing along information from Kelley to the FBI agents who conducted the investigation, but that agent was subsequently told by his superiors to steer clear of the case because they grew concerned that the agent had become obsessed with the investigation, the official said. The agent was a friend of Kelley and long before the case involving Petraeus got under way, the agent had sent Kelley shirtless photos of himself, according to this official. The Wall Street Journal first reported that this FBI agent was kept away from the case. 
 
 Cooper told The Associated Press Monday that Cantor notified the FBI's chief of staff of the conversation but did not tell anyone else because he did not know whether the information from a person he didn't know was credible. 
 
 "Two weeks ago, you don't want to start spreading something you can't confirm," Cooper said. 
 
 The FBI responded by telling Cantor's office that it could not confirm or deny an investigation, but assured the leader's office it was acting to protect national security. Cooper said Cantor believed that if the information was accurate and national security was affected, the FBI would, as obligated, inform the congressional intelligence committees and others, including House Speaker John Boehner. 
 
 One of the law enforcement officials who spoke to the AP said long-standing Justice Department policy and practice is not to share information from an ongoing criminal investigation with anyone outside the department, including the White House and Congress. The official said national security must be involved to notify Capitol Hill, and that was not the case in the Petraeus matter. 
 
 Petraeus' affair with Broadwell will be the subject of meetings Wednesday involving congressional intelligence committee leaders, FBI deputy director Sean Joyce and CIA Deputy Director Michael Morell. 
 
 Petraeus had been scheduled to appear before congressional committees on Thursday to testify about the Benghazi attack that killed four Americans, including U.S. Ambassador Chris Stevens. Morell is expected to testify in place of Petraeus. 
 
 Feinstein and others didn't rule out the possibility that Congress will try to compel Petraeus to testify about Benghazi at a later date, even though he has relinquished his CIA job. 
 
 ___ 
 
 Yost reported from Washington. Associated Press writers Nedra Pickler, Larry Margasak, Adam Goldman and Robert Burns contributed to this report. Dozier can be followed on Twitter (at)kimberlydozier. ||||| Exclusive 
 
 Broadwell’s notes to Jill Kelley were full of ‘cat-fight stuff,’ a source tells Michael Daly—but there were no overt threats, and Petraeus was barely mentioned. So why did the FBI jump in? 
 
 The emails that Jill Kelley showed an FBI friend near the start of last summer were not jealous lover warnings like “stay away from my man,” a knowledgeable source tells The Daily Beast. 
 
 The messages were instead what the source terms “kind of cat-fight stuff.” 
 
 “More like, ‘Who do you think you are? … You parade around the base … You need to take it down a notch,’” according to the source, who was until recently at the highest levels of the intelligence community and prefers not to be identified by name. 
 
 The base described is MacDill Air Force Base in Florida, where Kelley serves as an unpaid “social liaison.” The source reports that the emails did make one reference to Gen. David Petraeus, but it was oblique and offered no manifest suggestion of a personal relationship or even that he was central to the sender’s spite. 
 
 Kelley herself seemed mystified as to what was behind the emails, much less who sent them. 
 
 “I don’t know who this person is and I don’t want to keep getting them,” she told the FBI, as recounted by the source. 
 
 When the FBI friend showed the emails to the cyber squad in the Tampa field office, her fellow agents noted that the absence of any overt threats. 
 
 “No, ‘I’ll kill you’ or ‘I'll burn your house down,’” the source says. “It doesn’t seem really that bad.” 
 
 The squad was not even sure the case was worth pursuing, the source says. 
 
 “What does this mean? There’s no threat there. This is against the law?” the agents asked themselves by the source’s account. 
 
 At most the messages were harassing. The cyber squad had to consult the statute books in its effort to determine whether there was adequate legal cause to open a case. 
 
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 “It was a close call,” the source says. 
 
 What tipped it may have been Kelley’s friendship with the agent. The squad opened a case, though with no expectation it would turn into anything significant. 
 
 “They weren’t seeing this as the crime of the century,” the source says. 
 
 And certainly nobody was looking to do anything that might cause a huge fuss and maybe get them bounced from Tampa. The field office there is a $35 million palace with a second-floor fitness center whose plate-glass windows overlook Tampa Bay, and an eating area that includes an outdoor, screened-in extension for fed al fresco. The closest agents get to that in, say, cold and grimy New York is eating in their cars. 
 
 The agents soon determined that the emails were coming from Paula Broadwell. They then would have had to consult with the U.S. Attorney’s office in order to secure a search warrant enabling them to go into Broadwell’s email. 
 
 They apparently did so and are said to have found a number of nonclassified documents that seemed to have originated with Petraeus but had not been sent by an account bearing his name. And yet they did not seem to have been forwarded from anywhere. 
 
 The agents then determined that Broadwell and Petraeus had been communicating with each other via private email accounts. As the Associated Press reported on Monday, the pair would save unsent messages in their inboxes, and then log into each other's account to read them. 
 
 “She really knows him,” the agents told themselves, by the source’s account. 
 
 The question then was the nature of the connection. 
 
 “What it was and most importantly what it wasn’t,” the source says. 
 
 Some of the steamier messages made clear that it was an affair. The besotted Broadwell may have viewed the curvaceous Kelley as a threat. Broadwell may be able to run a six-minute mile with Petraeus, but Kelley looks like a woman who lets the guys do all the running—and in her direction. 
 
 Maybe Broadwell chanced to encounter Kelley on some occasion and felt snubbed. Or Broadwell could have just seen online photos of Petraeus and his wife visiting the mansion that Kelley shares with her doctor husband and three young children. Kelley likely assisted her 7-year-old daughter, Caroline, in posting an online photo album that includes a picture of the girl and her two sisters with Petraeus. 
 
 “I was with Ganrl Patrais?’ the girl’s handwritten caption reads. “He came to my haws.” 
 
 For Kelley to help post this if she were having an affair with the general would border on the pathological. Bad enough that the news of Kelley’s involvement in setting the case in motion broke just in time for reporters to swarm the house during Caroline’s seventh birthday party there, complete with bouncy castle. 
 
 Broadwell is herself married to a doctor and has two young children. Maybe the parallels were part of what set her off. Her father told the New York Daily News that there is “a lot more here than meets the eye,” though he declined say what that might be. 
 
 Whatever transpired, the FBI agents found no indication that it constituted a crime or a threat to national security. They confirmed this when they interviewed Broadwell and then Petraeus. They are both said to have been forthcoming and consistent, even telling the agents more than they already knew. 
 
 Petraeus seems to have been the first guy in memory not to lie about sex. And a good thing too, because lying to a federal agent is a crime. Martha Stewart found that out the hard way. 
 
 By that point, FBI headquarters almost certainly had been notified. One former agent with extensive experience estimates that it would have taken no more than 24 hours for word to get to Director Robert Mueller. A case that might never have been if the agents in Tampa had heeded their initial misgivings now presented the head of the FBI with a predicament in which there were no happy options. 
 
 In all electronic surveillance, including emails, the FBI is legally compelled to adhere to the principle of “minimization,” limiting the invasion of privacy as much as possible to what is specifically warranted. This applies even when a case involves the worst kinds of criminals. 
 
 Agents are required to abstain from even listening to such purely personal conversations as mushy talk between a mob killer and his mistress. Minimization in these instances may have saved lives, as Mafia wives are notably more liable to express their fury physically than, say, military spouses. The wife of one Gambino crime-family boss sent an email concerning her philandering husband that was unquestionably a death threat. She then followed it with an apology. 
 
 “I am sorry I misspelled ‘arsenic.’” 
 
 As the Tampa case did not involve a crime or a threat to national security, one might have expected the spirit of minimization to lead the FBI to keep any personal revelations within the bureau and not say anything to anybody. 
 
 Perhaps Mueller was worried that if it leaked out somehow he might be accused of being like the FBI’s first director, J. Edgar Hoover, who relished collecting dirt. Hoover was not shy about using it to blackmail even the president. Mueller might even have been accused to being party to a plot to muzzle Petraeus regarding the mess in Benghazi. 
 
 Mueller chose to refer the matter to Petraeus’s titular superior, the Director of National Intelligence, James Clapper. The justification was that Petraeus was the head of an organization where such personal entanglements are considered a threat to security by making an agent a target for blackmail. No Bond girls for our spies. Mark it as an added twist that Skyfall opened in the midst of all this. 
 
 The CIA double-no code aside, nobody could possibly believe that Petraeus would allow himself to be blackmailed into betraying the nation over an affair. But the principle of the boss adhering to the rules remained. And Clapper is said to have urged Petraeus to resign on his own terms rather than await the jackals. 
 
 Petraeus dutifully went to the White House to tender his resignation. Never mind that the Oval Office has witnessed much philandering over the decades with nobody having to resign. Never mind that Bill Clinton remains living proof of the silliness of modern puritanism. Our present president is by every indication a faithful husband, but he needed Clinton’s help to get reelected. 
 
 The fact that the resignation came immediately after the election, even though the case is said to have begun back in late May or the beginning of June, has made more than a few people wonder about the timing. 
 
 Whatever the truth in this regard, it remains pitifully ironic that Petraeus could come to such grief over a little sex under a desk in a war zone where thousands of people were and are earnestly seeking to blow other people to bloody bits. Shoot but don’t schtup? 
 
 And just because Broadwell performed the literary equivalent of sex under a desk does not mean that any actual sex is anybody’s business. 
 
 By the long-honored principle of minimization, the members of Congress who are demanding to know why they were not told earlier about Petraeus’s affair with his biographer should be asking another question. 
 
 They should instead be demanding to know why anybody outside the FBI was told anything at all. 
 

– David Petraeus and Paula Broadwell attempted to keep much of their communication secret by using a trick popular with both teens and terrorists, the AP reports: They shared an email account and saved unsent draft messages to one another, so both could log on and read them. The tactic, which is used by al-Qaeda, leaves a much fainter trace than actually sending messages. The Washington Post calls it a "well-worn online trick" that has "been around for quite some time"—it was even featured in a 2008 spy movie—and thus it didn't fool FBI investigators. The AP also reports that Petraeus was "shocked" when he learned that Broadwell allegedly sent threatening emails to Jill Kelley, the woman who eventually set off the FBI investigation. Those emails were said to contain "stay away from my man" type warnings, according to the AP, but a source tells the Daily Beast that's not so. Yes, the emails included "kind of cat-fight stuff," but they were "more like, 'Who do you think you are? ... You parade around the base ... You need to take it down a notch,'" the source says, and they included just one passing reference to Petraeus. Kelley was apparently disturbed by the emails, which were sent anonymously, but the FBI found no evidence of actual threats and almost decided not to pursue the case. Click for the latest from the Petraeus scandal.