Washington (CNN) Congressional investigators asked then-Secretary of State Hillary Clinton, along with 17 other Cabinet secretaries, whether she used a personal email in 2012, a question she ignored. 
 
 Clinton's email practices have come under sharp scrutiny in the wake of the revelation that she exclusively used a private domain name and server to conduct public business while at State. 
 
 The question came in a Dec. 13, 2012, letter, obtained by CNN and first reported by the New York Times , from Rep. Darrell Issa, then-chairman of the House Committee on Oversight and Government Reform, to an array of Cabinet secretaries. It was part of an investigation into the email policies and procedures imposed by the Obama administration on its officials. 
 
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 "Have you or any senior agency official ever used a personal email account to conduct official business?" Issa wrote in the form letter. "If so, please identify the account used." 
 
 Read More ||||| AP Photo Hillary Clinton used private email account for State Department business Emails sent by Clinton from her personal account weren't archived in official government records. 
 
 Thousands of emails Hillary Clinton generated as secretary of state were not archived as official government records because she used a private email account to conduct State Department business, the State Department acknowledged Monday. 
 
 Aides to the former secretary of state turned over 55,000 pages of emails from her personal account to the State Department in December at its request, a department official said. 
 
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 Clinton’s use of the personal account for work-related emails and the State Department’s effort to gain control over the information were first reported by The New York Times. Clinton did not use a State Department email account, the paper reported. 
 
 “Last year, the Department sent a letter to representatives of former secretaries of state requesting they submit any records in their possession for proper preservation. In response to our request, Secretary Clinton provided the Department with emails spanning her time at the Department,” State Department spokeswoman Jen Psaki said in a statement. 
 
 The Times story suggested that the private email trove came to light as the State Department worked to respond to requests for information from a special House committee probing the deaths of four Americans in a 2012 attack on U.S. facilities in Benghazi, Libya. 
 
 However, a State Department official who asked not to be named said Monday night that the request to Clinton and other former secretaries took place in October of last year and was independent of any inquiries from the Benghazi panel. 
 
 Psaki did acknowledge that the set of emails Clinton aides gave to the department recently contained some records relevant to the Benghazi committee’s document demands. 
 
 “After the State Department reviewed [Clinton’s] emails, we produced about 300 e-mails responsive to recent requests from the Select Committee” on Benghazi, Psaki said. 
 
 A bill President Barack Obama signed last November declared that official messages sent on personal email accounts must be copied to an employee’s official account or forwarded to such an account within 20 days. The law, which was not retroactive, allowed employees to be subject to disciplinary action for failing to archive records but it did not carry criminal penalties. 
 
 The disclosure about official emails in Clinton’s private email account comes following a flurry of reports about foreign fundraising by the Clinton Foundation as well as paid speeches by President Bill Clinton during his wife’s tenure as secretary of state. 
 
 Some of the stories, linked to Hillary Clinton’s expected announcement of presidential campaign in the coming months, have raised questions about the transparency and rigor of an ethics agreement that led to vetting of the former president’s speeches and business dealings. 
 
 It’s not illegal for an official to use a private email account for government business, but copies of all official emails are supposed to be forwarded to an official account so that they can be archived in accordance with government records laws. 
 
 Clinton’s emails were not archived on government’s servers, the Times said. 
 
 The fact that Clinton’s emails were not a part of official State Department records until recently means many of them would not have been located in response to Freedom of Information Act requests, subpoenas or other document searches conducted over the past six years. 
 
 That omission seems certain to generate controversy, litigation and more news coverage as various entities demand access to the email trove just as Clinton’s campaign for the White House is expected to be getting underway. 
 
 A potential rival of Clinton in the presidential campaign, former Gov. Jeb Bush (R-Fla.), called on the former secretary of state to make the collection of emails public. 
 
 “Hillary Clinton should release her emails. Hopefully she hasn’t already destroyed them,” Bush spokeswoman Kristy Campbell said. “Governor Bush believes transparency is a critical part of public service and of governing.” 
 
 Clinton spokesman Nick Merrill emphasized to the Times that emails Clinton sent to other government officials at their official accounts would have been archived as part of those accounts. In her statement, Psaki made the same point. 
 
 It appears, though, that until the recent retrieval of Clinton’s private emails, there would have been no official record of the secretary’s electronic correspondence with foreign officials or private individuals outside the government. 
 
 A bulletin issued by the National Archives and Records Administration in August 2013 said that “agency employees should not generally use personal email accounts to conduct official agency business.” 
 
 Although that notice emerged about eight months after Clinton stepped down as secretary of state, there were a variety of highly publicized public controversies prior to that time about officials using private email servers for official work. 
 
 In 2007, the Republican National Committee announced that a large volume of emails generated by 22 officials in President George W. Bush’s White House, including political adviser Karl Rove, had been deleted and were unavailable for congressional investigators. The officials used the GOP email system in an effort to separate official and political work, but may sometimes have mixed the two. 
 
 At the time, Democrats were highly critical of the practice. 
 
 In 2010, the then-chairman of the House Oversight and Government Reform Committee, Rep. Darrell Issa (R-Calif.) complained about reports that White House officials were using their personal emails to arrange meetings with lobbyists. 
 
 And in 2012, the House Energy and Commerce Committee reported that Obama aide Jim Messina used his personal email account to arrange a meeting with a pharmaceutical industry lobbyist during a critical moment for health-care reform legislation in 2010. 
 
 Back then, the White House said that officials who used personal accounts for official business were expected to forward those emails to official accounts. It is unclear whether Messina ever did. 
 
 Psaki said Monday that Secretary of State John Kerry is using official email and it is being properly archived. 
 
 “The Department is in the process of updating our records preservation policies to bring them in line with recent 2013 National Archives and Records Administration guidance. These steps include regularly archiving all of Secretary Kerry’s emails to ensure that we are capturing all federal records,” she said.
– Just when you thought Hillary Clinton's email brouhaha had moved on to other things, the New York Times uncovers an old letter congressional investigators sent Clinton asking about her email use. In the letter dated Dec. 13, 2012, House Oversight Committee chair Darrell Issa explicitly asks whether the then-secretary of state "or any senior agency official ever used a personal email account to conduct official business" and requests that the accounts be identified. He also asks about "alias" accounts and text messages, CNN reports. Clinton never replied and left the State Department weeks later on Feb. 1, 2013. On March 27 of that year, the department described its policies for personal email use for Issa, as he had also requested. "Employees may use personal email on personal time for matters not directly related to official business, and any employee using personal email 'should make it clear that his or her personal email is not being used for official business,'" the State Department's assistant secretary for legislative affairs wrote. A rep refused to answer questions yesterday about why it avoided mentioning Clinton's email use. However, a Clinton aide says "her usage was widely known to the over 100 department and US government colleagues she emailed, as her address was visible on every email she sent." Issa's initial letter was part of an investigation spawned when administration and EPA officials were found to be using private accounts for government business.