Congressional investigators first probed presidential candidate Hillary Clinton in late 2012 on whether she used a private email account while serving as secretary of state, TheNew York Times reported Tuesday. The revelation emerged in a December 2012 letter from Republican Rep. Darrell Issa, the chairman of the House Committee on Oversight and Government Reform, regarding the Obama administration’s use of personal email. Clinton did not respond to the letter before leaving office and the State Department’s reply nearly two months later ignored the question and only provided a description of its email policies.