Hillary Clinton looks set to come under renewed pressure to explain herself after a letter revealed she had been asked about her use of private email by a House committee two years ago - but refused to answer . Representative Darrell Issa asked then Secretary of State Clinton whether she , or any of her senior staff , had used a personal email account 'to conduct official business ' in December 2012 . But Issa , who wrote as chairman of the House committee on oversight and government reform , was ignored until more than a month after Clinton had stepped down in February 2013 . And even then , the reply did not answer the question - instead going into detail over the State Department 's email policy . Silence : Representative Darrell Issa ( left ) asked the State Department about the use of personal email for official business in December 2012 , but did n't receive any answer until Clinton ( right ) had left the department . The leaked letter , obtained by the New York Times , casts a further shadow over Clinton just days into her bid to become the Democrat 's 2016 presidential candidate . The former First Lady found herself at the centre of a storm in recent months after it was revealed she used her personal address during her time as Secretary of State . Even her Twitter profile picture was dragged into the row : it showed her on her Blackberry apparently sending emails while en route to Libya in September 2011 . But there is no record of any emails on her official account that day - and she has since removed the picture from her account . Clinton has confirmed that she exclusively used her private account , calling it a matter of 'convenience ' , admitting to deleting thousands of emails . Clinton , however , has insisted every relevant email was now in the hands of the State Department . But critics say by using her personal email account , she has avoided scrutiny . The presidential hopeful handed over 55,000 emails sent from her personal email account between 2009 and 2013 - her time as Secretary of State - but it is not yet known what they contained . However , it has already been claimed that the documents have 'huge gaps ' . Shadow : Clinton is likely to want to play down this latest revelation as she begins campaigning in Iowa . Campaigning : Clinton is hoping to win over voters with a more personal approach than in 2007 . Clinton is likely to want to play down these latest revelations , as she begins a campaign for nomination which is set to last until the end of June next year . A Clinton aide told the New York Times on Tuesday 'her usage was widely known to the over 100 department and U.S. government colleagues she emailed , as her address was visible on every email she sent ' . Clinton is currently on a two day tour of Iowa , opening her 2016 campaign with visits to a family-owned produce company and speaking with small-business leaders outside Des Moines . The decision to focus on smaller , more personal interactions during the campaign is in stark contrast to 2007 , when she spoke to huge crowds . The grandmother-of-one will spend a second day in Iowa campaigning today .
Letter to White House in December 2012 asked about personal email . But there was no response until March 2013 - seven weeks after Clinton left . Reply did not answer query about personal email use for official business . Latest revelation casts further shadow as Clinton begins State Department bid .